Legacy Resources

Frequently Asked Questions

How do I know if I need a new roof?

Age -Typical shingle roofs last 12 to 20 years. There is variation in life due to shingle quality, color, sun exposure and ventilation under the roof.

Appearance - If you have shingles that have broken off, or look buckled or warped, or have lost some of the granule surfacing, it may be time for replacement.

Leaks - Probably not the best way to find out. By the time you see evidence of water leaking inside the house, it has probably been leaking for quite a while prior. This leaking can cause expensive structural damage to the rafters and the boards on top of them, not to mention the damage to your ceilings and walls. It is usually much less expensive to replace a roof before you see leaks.

Note: Legacy will gladly send an inspector to your home, free of charge, and give you a no obligation assessment.

Will Legacy really install my new roof in one day?

Yes. Typically, your new Legacy will be installed in one day. The installation includes tear off, haul, new roof and clean up. Speed does not compromise quality. We pride ourselves on efficiency and the fact that we can mobilize and organize a job site with a large and efficient workforce.

When is the best time to put on a roof?

There is no "best time" to put on a roof. Legacy installs roofs year round and there will be no difference in quality, look, or longevity whether the roof is installed in January of July.

What about installing a roof in the winter?

Legacy shingles are designed to be installed year round. A rubberized component of the shingle makes them perfect for wintertime installation.

What about attic ventilation?

The perfect times to fix, upgrade, or maintain the correct balance of air flow/ventilation in your attic is at time of roof replacement. Legacy will inspect your attic and make any necessary recommendations. Attic ventilation is a major factor in how long your roof will last.

Do you use stapes or nails?

Though many companies use staples to install their shingles, because it is cheaper, Legacy only uses treated roofing nails specifically made for roofing only.

What causes the stains on my old roof?

Likely, the stains you see on your old roof are a result of algae growth. More time than not this algae growth is more prevalent on the North and East facing slopes, due to less sun exposure. When you install a Legacy, our shingles are treated to resist algae.

What is an ice dam?

An ice dam is an area on the roof that tends to build up with ice. Poor ventilation and constricted drainage areas are causes of ice dams. We can often eliminate ice dams through ventilation. Every Legacy is designed to eliminate any interior leakage as a result of ice dams.

Does Legacy use Ice Guard?

Yes, but we don\'t stop there! Every Legacy goes one step further with a special underlayment to protect the entire roof for ice dam leakage.

If my roof leaks, will there be long term damage?

A leaking roof cannot be ignored as it often causes serious damage to other components of your home, not to mention the possibility of mold. A leaking roof should be looked at immediately. Note: Legacy will gladly send an inspector to your home, free of charge, and give you an honest opinion. There is no obligation or pressure to buy anything.

What if it rains during my roof installation?

When Legacy does your roof we eliminate the weeklong process (that almost always assures rain) by installing your roof in 24-48 hours, the vast majority of roofs, Legacy is able to successfully complete in one day.

Will my plants and lawn get damaged? How about rusty nails?

Legacy takes pride in protecting your plants and shrubs. We realize how important they are to you. We protect your yard with tarps and even run an industrial magnet roller throughout your yard as part of the clean-up process to assure no hidden rusty nails.

Does Legacy do insurance work?

Yes, we have experience with all major insurance carriers and can negotiate on your behalf and in your best interest.

How does hail damage a roof?

Hail knocks the protective granules off the shingles exposing the matt beneath. Once the matt is exposed to the sun the shingle will rapidly start to degrade. Hail damage is typically covered by homeowners insurance. Note: Legacy will gladly send an inspector to your home, free of charge, and give you an honest opinion. There is no obligation or pressure to buy anything.

Will my homeowners insurance pay for a new roof if I have wind or hail damage?

Yes. Wind and Hail damage can be subjective and therefore different opinions can arise as to the extent of the damage. It is best to have someone representing your best interest when your insurance adjuster inspects. Legacy will gladly help you with your insurance company.

What if I have been turned down by insurance for wind or hail damage?

Legacy will gladly send an inspector to your home, free of charge, and give you an honest opinion. There is no obligation or pressure to buy anything.

Does Legacy work year-round?

Yes, and in some years we install as many roofs in the winter as we do in the summer.

Can a new roof lower my utility bills?

A new roof will not lower your utility bills, however, a properly designed roof and ventilation system will absolutely lower your utility bills by removing summer heat and winter humidity from attic spaces.

Do I have to be home during the roofing work?

No. All work will be done on the outside of your home so we do not have to come into your home.

If I have missing shingles will my roof eventually leak?

Yes. Missing shingles must be corrected as soon as possible.
▪ Note: Legacy will gladly send an inspector to your home, free of charge, and give you a no obligation assessment.

Does Legacy recycle?

Yes. Legacy is a pioneer in shingle recycling. Shingles removed from your roof are ground up and used as road bed material when and wherever possible.

My existing roof is 15 years old and failing. Why did it only last 15 years?

Our experience is that a 20 year rated shingle lasts 12 to 14 years and a 30 year shingle lasts 14 to 17 years at best. The shingles that your parents may have had on their home were made of better materials with less fillers. Today, a lot of by products can go into the shingles affecting their longevity. When you buy a Legacy your roof is guaranteed for as long as you live in your home. Our shingle is made without byproducts and is rubberized to last a lifetime.

Do you offer financing?

Yes. We offer a variety of financing and can help you, confidentially and quickly.

Do you accept credit cards?

Yes, Legacy accepts all major credit cards. Legacy has a number of financing options to choose from as well.

Roofing Glossary

ACIL: American Council of Independent Laboratories

Acrylic Coating: A coating system with an acrylic resin base

Acrylic Resin Polymers of acrylic or methacrylic monomers often used as a latex base for coating systems.

Active: Will corrode in the presence of moisture or a "noble" metal.

Adhere: The clinging of one surface to another; either molecularly or otherwise.

Adhesion: The state of adhering

AFA: American Fiberboard Association

AGC: Associated General Contractors of America

Aggregate: A surfacing or ballast for a roof system. Aggregate can be rock, stone, crushed stone or slag, water-worn gravel, crushed lava rock or marble chips.

AHA: American Hardboard Association

AIA: American Institute of Architects

Air Blown Asphalt: Asphalt produced by blowing air through molten asphalt held at an elevated temperature. This procedure is used to modify properties of the asphalt.

Alligatoring: The cracking of the surfacing bitumen on a built-up roof, producing a pattern of cracks that resemble an alligator's hide.

Aluminized Steel: Sheet steel with a thin aluminum coating on the surface to enhance the steel's ability to withstand weathering.

Aluminum: A non-rusting metal used in roofing for metal roofing and the fabrication of gutter and flashings.

Ambient Temperature: The temperature of the air.

Anodic: When two metals are connected in an electrolyte, they will form a galvanic cell, with the higher metal in the galvanic series being the anode. The anodic will oxidize and produce an electrical current which protects the cathode from corrosion.

ANSI: American National Standards Institute

APA: American Plywood Association

APP: See Atactic Polypropylene.

Application Rate: The rate at which a material is applied per unit area.

Apron Flashing: A flashing located at the low end of a curb or penetration.

Architectural Panel: A metal roof panel that usually requires solid decking underneath.

Architectural Shingle: Shingle that provides a dimensional appearance. See also Dimensional Shingle.

Area Divider: A flashed assembly usually extending above the surface of the roof that is anchored to the roof deck. It is used to relieve thermal stresses in a roof system where an expansion joint is not required, or to separate large roof areas.

ARMA: Asphalt Roofing Manufacturers Association

ASA: American Subcontractors Association

Asbestos: An incombustible fibrous mineral form of magnesium silicate formerly used for fireproofing and sometimes used for the reinforcement of roofing materials.

ASC: Associated Specialty Contractors

ASHI: American Society of Home Inspectors

ASHRAE: American Society of Heating, Refrigerating & Air-Conditioning Engineers, Inc.

Asphalt: A substance left as a residue after evaporating or otherwise processing crude oil or petroleum. Asphalt can be refined to conform to various roofing grade specifications:

     Dead-Level Asphalt: A roofing asphalt conforming to the requirements of ASTM Specification D 312, Type I. This asphalt is for use in roofs which do not exceed a ¼ in 12 slope (2%).

   Flat Asphalt: A roofing asphalt conforming to the requirements of ASTM Specification D 312, Type II. This asphalt is for use in roofs which do not exceed a ½ in 12 slope (4%).

   Steep Asphalt: A roofing asphalt conforming to the requirements of ASTM Specification D 312, Type III. This asphalt is for use in roofs which do not exceed a 3 in 12 slope (25%).

   Special Steep Asphalt: A roofing asphalt conforming to the requirements of ASTM Specification D 312, Type IV. This asphalt is for use in roofs which do not exceed a 6 in 12 slope (50%).

Asphalt Emulsion: A mixture of asphalt particles and an emulsifying agent such as bentonite clay and water.

Asphalt Felt: An asphalt-saturated and/or an asphalt-coated felt membrane. (See also Felt.)

Asphalt Primer: See Primer.

Asphalt Roof Cement: The proper name for Plastic Cement and Flashing Cement. Asphalt roof cement consists of solvent-based bitumen, mineral stabilizers, and other fibers (sometimes asbestos). Asphalt roof cement is categorized by ASTM standard D 2822-91 (1997) or for non-asbestos, ASTM standard D 4586-93.

   Plastic Cement is for use on low-slope surfaces, conforms to ASTM Specification D 312, Type I; Specification D 449, Types I or II; or Specification D 946. Plastic Cement is self-sealing, adhesive and ductile and is classified by ASTM Standard D 2822-91 Asphalt Roof Cement, and D 4586-92Asphalt Roof Cement, Asbestos-Free, Types I and II.

   Flashing Cement can be used on vertical surfaces and has a high softening point, low ductility and conforms to the requirement of ASTM Specification D 312, Types II or III; or Specification D 449, Type III.


ASTM: American Society for Testing and Materials

Atactic Polypropylene: A group of high molecular weight polymers formed by the polymerization of propylene.

Attic: The open area above the ceiling and under the roof deck of a steep-sloped roof.

AWPA: American Wood Preservatives Association

AWS: American Welding Society


Back-Nailing: The method of fasteningthe back or upper side of a ply of roofing felt or other component in a roofsystem so that the fasteners are covered by the following ply.

Back-Surfacing: A fine mineral materialon the back side of roofing materials such as roll roofing to keep them fromsticking together while packaged.

Ballast: A material installed over the top of a roofmembrane to help hold it in place. Ballasts are loose laid and can consist ofaggregate, or concrete pavers.

Bar Joist: See Steel Joist

Barrel Roof: A roof configuration with a partial cylindrical shape to it.

Base Flashing (membrane base flashing): Plies of roof membrane material used to seal a roof at the vertical plane intersections, such as at a roof-wall and roof-curb junctures. (See also Flashing.)

Base Ply: The primary ply of roofing material in a roof system.

Base Sheet: An asphalt-impregnated, or coated felt used as the first ply in some built-up and modified bitumen roof systems.

Batten: (1) A strip of wood usually fastened to the structural deck for use in attaching a primary roof system such as tile; (2) A plastic strip, wood strip, or metal bar which is used to fasten or hold the roof and/or base flashing in place, A.K.A. Termination Bar.

Bermuda Seam: A metal roof that has a step profile.

Bird Bath: Small, inconsequential amounts of water on a roof that quickly evaporate.

Bird Screen: Wire mesh installed over openings in order to prevent birds from entering a building or roof cavity.

Bitumen: Any of various flammable mixtures of hydrocarbons and other substances, occurring naturally or obtained by distillation from coal or petroleum, that are a component of asphalt and tar and are used for surfacing roads and for waterproofing.

Bitumen-Stop: A continuous seal for preventing bitumen from leaking down into or off a building. Is constructed by extending the base sheet or other non-porous ply of felt beyond the edge of the field plies. It is then turned back onto the top of the system and adhered. See also Envelope.

Bituminous Emulsion: Bituminous particles suspended in water or other solution. See also Asphalt Emulsion.

Blackberry: See Tar Boil.

Bleeder Strip: A starter strip placed along rake edges for use in asphalt shingle roofing. See also Rake-Starter.

Blind-Nailing: The use of nails so that they are not exposed to the weather in the finished roofing system. See Back-Nailing

Blister: A pocket of air trapped between layers of felt or membrane. Blisters are usually caused by water or other foreign substances.

Blocking: Pieces of wood built into a roof assembly used to stiffen the deck around an opening, support a curb, or for use as a nailer for attachment of membranes or flashing.

Blown Asphalt: See Air Blown Asphalt.

Blueberry: A small bubble found in the flood coat of an aggregate-surfaced built-up roof. See also Tar Boil.

BOCA: Building Officials and Code Administrators, International, Inc.

BOMA: Building Owners & Managers Association, International

Bond: The force(s) holding two components in positive contact.

Bonding Agent: A chemical agent used to create a bond between two layers.

Boot: A piece of material preformed to protect roof penetrations from dirt, moisture and other foreign and/or damaging substances.

Brake: A piece of equipment used for forming metal.

Bridging: When membrane is unsupported at a juncture.

British Thermal Unit (BTU): The heat energy necessary to raise the temperature of one pound of water one degree Fahrenheit, a joule.

Brooming: Embedding a ply of roofing material into hot bitumen or adhesive by using a broom, squeegee, or other piece of equipment to eliminate voids and help ensure adhesion.

Buckle: A long, tented displacement of a roof membrane. Can occur over insulation and deck joints.

Built-Up Roof Membrane: A roof membrane consisting of layers of bitumen, which serves as the waterproofing component, with plies of reinforcement fabric installed between each layer. The reinforcement material can consist of bitumen-saturated felt, coated felt, polyester felt or other fabrics. A surfacing is generally applied and can be asphalt, aggregate, emulsion or a granule-surfaced cap sheet.

Bulb-Tee: A steel reinforcing member used when constructing pre-stressed, poured gypsum decks. When the gypsum is poured, it surrounds the Bult-Tee.

Bundle: An individual package of shingles or shakes.

BUR: An acronym for Built-Up Roof. See Built-Up Roof.

Butadiene: A colorless, highly flammable hydrocarbon, C4H6, obtained from petroleum and used in the manufacture of synthetic rubber.

Butt Joint: Where two separate, adjacent pieces of material abut.

Butyl: A hydrocarbon radical, C4H9. Butyl has a rubber-like consistency, is formed from the copolymerization of isobutylene and isoprene and is used primarily in sealants and adhesives.

Butyl Rubber: A butyl-based, synthetic elastomer.

Butyl Tape: A sealant tape used in numerous sealant applications such as sealing sheet metal joints.



CABO: Council of American Building Officials

Calender: A machine used to laminate sheeting or forapplying coating with a specified thickness and/or surface attribute.

Calendering: A specific process usedto manufacture some membranes such as PVC.

Camber: A slight convex curve of a surface.

Canopy: An overhang, usually over entrances or driveways.

Cant: (1) Short for Cant Strip; (2) The act of installing foam at a right angle adjunct.

Cant Strip: A triangular-shaped strip of material used to ease the transition from a horizontal plane to a vertical plane. Cant strips can be made of wood, wood fiber, perlite, or other materials.

Cap Flashing: A material used to cover the top edge of base flashings or other flashings. (See also Coping.)

Cap Sheet: A granule-surfaced membrane often used as the top ply of BUR or modified roof systems.

Capacitance Meter: A device for locating moisture within a roof system by measuring the ratio of the change to the potential difference between two conducting elements that are separated by a non-conductor.

Catalyst: A substance that effects a chemical reaction and/or the rate at which a chemical reaction takes place. In roofing, catalysts are used in SPF roofing.

Cathodic: metals low in the Galvanic Series.

Caulk: A material with no elastomeric properties used for sealing joints.

Caulking: The act of sealing a joint or of material.

Cavitation: The vaporization of a liquid under the suction force of a pump which can create voids within the pump supply line. Cavitation will result in off-ratio foam in Sprayed Polyurethane Foam applications.

CCF: 100 cubic feet.

C-Channel: A structural framing member that, when viewed cross-sectionally, has the shape of a "C".

Cellulose: A complex carbohydrate, (C6H10O5)n, that is composed of glucose units, forms the main constituent of the cell wall in most plants, and is used in the manufacturing of organic roofing materials.

CERL: Construction Engineering Research Laboratory

CG&E: See Chopped Glass and Emulsion.

Chalk: A powdery residue on the surface of a material.

Chalk Line: (1) A string on a reel in a container that can hold chalk; (2) A line made on by pulling taut a string coated with chalk and snapping it.

Channel Flashing: Flashing with a built-in channel for runoff; used where roof planes intersect other vertical planes.

Chemical Resistance: A materials ability to retain its properties when it comes into contact with certain chemicals.

Chlorinated Polyethylene1 (CPE): CPE is a flexible material with high tear strength, good chemical resistance and patency towards UV radiation. As a result of the high chlorine content (typically 30%) it is inherently difficult to ignite, but releases hydrogen chloride during combustion. It suffers from an extremely high permeability to gas. Resistance to most inorganic chemicals is generally good, while resistance to hydrocarbons increases with increasing chorine content. The material is used mainly as an impact modifier for PVC and, to a lesser extent, LDPE and HDPE film.

Chlorosulfonated Polyethylene (NRCA Definition): A synthetic, rubber-like thermoset material, based on high molecular weight polyethylene with suphonyl chloride, usually formulated to produce a self-vulcanizing membrane. Chlorosulfonated Polyethylene or CSPE. Best know as Hypalon™, it was developed in 1951 by DuPont.

Chopped Glass and Emulsion (CG&E): A roof coating that consists of asphalt or clay emulsion and glass fiber reinforcement. The glass fiber comes in rope form and is mechanically chopped into small pieces and then mixed with the emulsion at the end of the spray gun so that the mixture is complete by the time the surfacing hits the top of the roof. Standard mixture is 9 gallons of emulsion and 3 pounds of glass fiber for every 100 square feet (36.5 Liters of emulsion and 1.5 kg of chopped glass for every 10 square meters). The CG&E coating is then usually surfaced with a fibered aluminum roof coating at rate of 1.5 gallons per 100 square feet (6 Liters per 10 square meters).

Cladding: A material used to cover the exterior wall of a building.

Cleat: A continuous metal strip used to secure two or more metal roof components together. Commonly used along with coping or gravel stop on tall buildings.

Clerestory (Clearstory): A room that extends above an abutting roof section of a building.

Clip: A small cleat. See Cleat.

Clipped Gable: A gable cut back at the ridge in a small hip configuration.

Closed-Cut Valley: A method of valley application in which shingles from one side of the valley extend across the valley while shingles from the other side are installed over the top of those and then trimmed back approximately 2 inches from the valley centerline.

Closure Strip: A material used to close openings created by joining metal panels or sheets and flashings.

Coal Tar Bitumen: A proprietary trade name for Type III coal tar used in dead-level or low-slope built-up roofs. It is not for use in roofs exceeding ¼" in 12" (2%) slope.

Coal Tar Pitch: A type of coal tar used in dead-level or low-slope built-up roofs. It is not for use in roofs exceeding ¼" in 12" (2%) slope.

Coal Tar Felt: A roofing membrane saturated with refined coal tar.

Coal Tar Roof Cement: A trowelable mixture of processed coal tar base, solvents, mineral fillers and/or fibers.

Coarse Orange Peel Surface Texture: A surface showing a texture where nodules and valleys are approximately the same size and shape. This surface is generally acceptable for installing a protective coating.

Coated Base Sheet: An asphalt-saturated base sheet membrane later coated with harder, more viscous asphalt, thereby increasing its impermeability to moisture.

Coated Felt: An asphalt-saturated ply sheet that has also been coated on both sides with harder, more viscous asphalt.

Coating: A layer of material that is spray, roller, or brush applied over a surface for protection or sometimes decoration.

Cohesion: Mutual attraction by which the elements or particles of a body or substance are held together.

Coil Coating: The application of a finish to a coil of metal or other material.

Cold Forming: The process of shaping metal into desired configurations at ambient room temperature.

Cold Process Built-Up Roof: A roof consisting of multiple plies of roof felts laminated together with adhesives that usually come right out of a can or barrel and require no heating.

Collector Head: A component used to direct water from a through-wall scupper to a downspout. Also known as a Conductor Head.

Column: A vertical structural member placed on a footing or foundation used to support horizontal above-ground building components.

Combing Ridge: A term used to describe an installation of finishing slate at the ridge of a roof whereby the slates on one side project beyond to the apex of the ridge.

Combustible: Capable of igniting and burning.

Composition Shingle: A type of shingle used in steep-slope roofing and generally comprised of weathering-grade asphalt, a fiber glass reinforcing mat, an adhesive strip, and mineral granules.

Compounded Thermoplastics1 (NRCA Definition): A category of roofing membranes made by blending thermoplastic resins with plasticizers, various modifiers, stabilizers, flame retardants, UV absorbers, fungicides, and other proprietary substances, alloyed with proprietary organic polymers. Some of the membranes listed in this generic category are CPA, EIP, NBP, and TPA.

Concealed-Nail Method: A method of installing asphalt roll roofing material in which all nails or fasteners are driven into the underlying roofing and covered by an overlapping course.

Condensate: The liquid resulting from condensation.

Condensation: The conversion of water vapor to liquid state when warm air comes in contact with a cold surface. (See also Dew Point.)

Conduction: The transmission or conveying of something through a medium or passage, especially the transmission of electric charge or heat through a conducting medium without perceptible motion of the medium itself.

Conductor Head: A component used to direct water from a through-wall scupper to a downspout. Also known as a Collector Head.

Construction Joint: A constructed joint where two successive installments of concrete come together.

Contact Cements: Adhesives used to adhere or bond roofing components.

Coping: the piece of material used to cover the top of a wall and protect it from the elements. It can be constructed from metal, masonry, or stone.

Copper: A reddish-brown element that conducts heat and electricity very well. It is also used as a primary roof material as well as a flashing component. Copper turns a greenish color after being exposed to the weather for a length of time and appears in the middle of the Galvanic Series.

Cornice: A horizontal projecting part that crowns the wall of a building.

Counter Batten: Wood strips installed vertically on sloped roofs over which horizontal battens are secured.

Counterflashing: Formed metal sheeting secured to walls, curbs, or other surfaces, for use in protecting the top edge of base flashings from exposure to weather.

Course: (1) The term used for each row of roofing material that forms the roofing or flashing system; (2) One of multiple layers materials applied to a surface. For example, a three-course flashing consists of a layer of mesh or other reinforcing material sandwiched between two layers roofing cement.

Cove: In roofing, a heavy bead of sealant material installed at the point where vertical and horizontal planes meet. It is used to eliminate the 90° angle. See also Fillet.

Cover Plate: A metal strip sometimes installed over the joint between formed metal pieces.

Coverage: The surface area covered by a material.

CPA: Copolymer Alloy.

CPE: Chlorinated Polyethylene.

Crack: A separation or fracture occurring in a material. See also Split.

Cream Time: Time in seconds at a given temperature when the A and B (isocyanate and resin) components of SPF will begin to expand after being mixed.

Creep: Movement of roof membrane causing the roof system to be deformed

Cricket: A roof component used to divert water away from curbs, platforms, chimneys, walls, or other roof penetrations and projections. See also Saddle.

Cross Ventilation: The effect of air moving through a roof cavity between vents.

CRREL: Cold Regions Research and Engineering Laboratory

Crow's Nest: See Cupola.

CSI: Construction Specifications Institute

CSM: ASTM designation for Chlorosulfonated polyethylene. (See CSPE.)

CSPE: Chlorosulfonated polyethylene.

Cupola: A relatively small roofed structure set on the ridge of a main roof area. Also known as a Crow's Nest.

Curb: (1) A raised member used to support skylights, HVAC units, exhaust fans, hatches or other pieces of mechanical equipment above the level of the roof surface, should be a minimum of eight inches (8") in height; (2) A raised roof perimeter that is relatively low in height.

Cure: A process by which a material is forms permanent molecular linkages by exposure to chemicals, heat, pressure, and/or weathering.

Cure Time: The time necessary to effect curing.

Curing Agent: A material additive that alters chemical activity between the components resulting in a change in the rate of cure.

Curing Compound: A liquid that is applied to newly installed concrete which slows water loss while curing.

Cutback: Bitumen thinned by solvents that is used in cold-process roofing adhesives, roof cements, and roof coatings.

Cut-off: A detail designed to seal and prevent lateral water movement in an insulation system, and used to separate different sections of a roofing system.

Cutout: The open area between shingle tabs. Also known as a "throat".


Dampproofing: Treatment of a surfaceor structure to resist the passage of water in the absence of hydrostaticpressure.

Dead Level: Refers to a roof with noslope or pitch.

Dead-Level Asphalt: A roofingasphalt conforming to the requirements of ASTM Specification D 312, Type I.This asphalt is for use in roofs which do not exceed a ¼ in 12 slope (2%).

Dead Loads: Permanent, non-movingloads on a roof resulting from the weight of a building's components,equipment, and the roof system.

Deck: The structural component of the roof of a building which provides the substrate to which the roofing system is applied.

Decking: See Deck.

Deflection: The downward displacement of a structural member under load.

Degradation: A decline in the appearance, structure, or properties, of a material or substance.

Delamination: Separation of laminated layers of a material or system.

Dew Point Temperature: The temperature at which water vapor turns to liquid in cooling air at the existing atmospheric pressure and vapor content.

Diaphragm: A type of structural roof deck capable of resisting shear that is produced by lateral forces such as wind or seismic loads.

Diffusion: The movement of a substance such as water vapor from regions of high concentration to regions of lower concentration

Dimensional Shingle: A shingle that is textured, or laminated to produce a three-dimensional effect. Also known as Laminated and Architectural Shingles. Please be aware that there are also shingles being produced that can be classified as Dimensional but not as Laminated. These shingles are comprised of a single piece of material rather than two different materials laminated together.

Dimensional Stability: The ability of a material to retain its current properties and to resist a change in size resulting from exposure to temperature changes and moisture.

Dome: A roof with a partial-spherical shape.

Dormer: A framed projection through the sloping plane of a roof.

Double Coverage: Installing roofing so that there is twice the materials used resulting in a double layer of roofing.

Double Graveling: Installing one layer of gravel in a flood coat of hot bitumen, removing the excess gravel and then installing a second layer of gravel in another flood coat of hot bitumen.

Downspout: A conduit for carrying water from a gutter, scupper, drop outlet or other drainage unit from roof to ground level. Also known as a Leader Pipe.

Drain: a device used to carry water off of a roof.

Drip Edge: A steel flashing bent at a 90º angle that is placed along the outer perimeter of steep sloped buildings; used to help direct runoff water away from the building. Drip Edge resembles nosing except that it has an outwardly-angled bottom edge (preferably hemmed). To see the difference between Drip Edge and Nosing.

Dry Bulb Temperature: The temperature of air in degrees Fahrenheit measured by an ordinary thermometer.

Dry Film Thickness: The thickness in mils (thousandths of an inch), of a dried coating or mastic.

Dry-In: (1) The process of installing the underlayment in steep slope roofing; (2) Making a low-slope roof watertight. Does not always mean getting all of the required plies installed.

Dry Rot: Wood rot caused by certain fungi. Dry rot can result from condensation build-up, roof leaks that go untended, or from other problems. Dry rot will not remain localized. It can spread and damage any lumber touching the affected area.

Dual Level Drain: An item that will permit drainage at two different levels.

Dynamic Load: Any moving load on a roof such as people and equipment. Wind can also be considered a Dynamic Load.


Eave: A roof edge that extends out past the exteriorwall line.

Eaves-Trough: Another name for Gutter.

ECH: Polyepichlorohydrin. See also Epichlorohydrin.

Edge Stripping: Roofing material used toseal perimeter edge metal and the roof itself.

Edge Venting: The installation of ventmaterial along a roof edge (e.g., Starter Vent) as part of a ventilationsystem. Edge vent material should be used in conjunction with other ventingmaterial (e.g., ridge vent) as it not intended for use by itself.

Elastomer: A material which, after being stretched, will return to its original shape.

Elastomeric: Properties of a material that will permit it to return to its original shape after being stretched.

Elastomeric Coating: A coating that can be stretched to twice its dimensions and that will return to original when tension is released.

Elongation: The ability of a material to be stretched or lengthened.

Embedment: In roofing, to uniformly press one material into another, such as aggregate into bitumen, roofing felt into bitumen, or granules into a coating.

Emulsion: Fine particles suspended in a liquid solution. See also Asphalt Emulsion and Bituminous Emulsion.

End Lap: The extension of one component of material past the end of an adjacent piece of material.

Envelope: A continuous seal for preventing bitumen from leaking down into or off a building. Is constructed by extending the base sheet or other non-porous ply of felt beyond the edge of the field plies. It is then turned back onto the top of the system and adhered. See also Bitumen-Stop.

EPDM: Ethylene Propylene Diene Monomer.

Epichlorohydrin (ECH): A synthetic rubber material similar to EPDM with a stronger resistance to animal fats and oils than EPDM.

Epoxy: A type of synthetic, thermosetting resins that produce tough, hard, chemical-resistant coatings and adhesives.

Equipment Screen: A nonstructural wall or screen constructed around rooftop equipment such as HVAC units, curbs, etc. to hide the look of the equipment and make the structure more aesthetically pleasing.

Equiviscous Temperature (EVT): The temperature at which a bitumen attains the proper viscosity for use in built-up roofing. There is usually a twenty-five degree Fahrenheit (25° F) variance permitted above and below the recommended EVT. The EVT is measured in application equipment just prior to application using a standard thermometer or it can be measured just after application using a laser thermometer.

The following tables have SAMPLE EVT temperatures.


Asphalt Type

Mop Application (° F)

Mechanical Spreader Application (° F)

Type I Dead Level

350 ± 25

375 ± 25

Type II Flat

400 ± 25

425 ± 25

Type III Steep

425 ± 25

450 ± 25

Type IV Special Steep

450 ± 25

475 ± 25



Coal Tar Type

Mop Application (° F)

Mechanical Spreader Application (° F)

Type I Pitch

360 ± 25

380 ± 25

Type III Bitumen

375 ± 25

400 ± 25


Ethylene Propylene Diene Monomer (EPDM): A thermoplastic rubber with high tear strength that can be cross-linked by both peroxides and sulfur.

EVT: Equiviscous Temperature

Exhaust Vent: A device used to vent air from the roof cavity with vents that are installed on or near the higher portions of the roof such as the ridge.

Expansion Cleat: A cleat designed to handle thermal movement of the metal roof panels.

Expansion Joint: A built-in separation between building sections to allow for free movement between the sections without damaging the buildings structural components.

Exposed-Nail Method: A method of installing roll roofing materials to where all nails/fasteners are visible and exposed to the elements.

Exposure: The portion of the membrane that is not overlapped by the succeeding ply or course. Or, the portion of the roofing material exposed to the weather after being installed.

Extrusion: The process of manufacturing and/or shaping a material by forcing it through a die.

Eyebrow: A small, shed roof protruding from the main roof or located on the side of a building below the level of the main roof.


Factory Mutual Research Corporation (FMRC): As it relates to roofing - a division of Factory Mutual System thattests and classifies roof components and systems for their resistance tofire, traffic, impact, weathering, and wind-uplift. The various organizationsof Factory Mutual are owned or directed by Allendale Insurance, Arkwright,and Protection Mutual Insurance.

Factory Seam: A splice/seam made inthe roofing material by the manufacturer. It is preferable duringinstallation to cut these splices out of the membrane.

Fading: Losing brightness or brilliance : dim

Fallback: A reduction in the softening point temperature of asphalt that occurs when asphalt is overheated for pro-longed periods of time. See also Softening Point Drift.

Fascia: Vertical roof trim located along the perimeter of a building, usually below the roof level. Its use can be either decorative or for waterproofing.

Fasteners: Devices used to secure roof system components.

Feathering Strips: Strips of wood that are placed along the butt ends of wood shingles to form a somewhat smooth surface so that the shingles can be roofed over without removal.

Felt: A roofing sheet made of interwoven fibers. The fibers can be wood or vegetable for Organic Felts, glass fibers for fiberglass felts, polyester, or asbestos.

Felt Machine: A machine that will install bitumen and felt at the same time.

Ferrule: A metal sleeve used as a spacer to keep gutter from being beat up when secured to fascia with spikes.

Fiberglass Insulation: Insulation composed of glass fibers used to insulate walls and roofs. It can be rigid board or blanket insulation.

Field of the Roof: Refers to the central part of a roof away from the perimeter.

Field Seam: A non-factory material seam made by joining overlapping seams together with adhesives, heat welders, or other means.

Filler: An inert ingredient added to roofing materials in order to alter their physical characteristics.

Fillet: A sealant material installed at horizontal and vertical planes to remove 90° angles.

Film: A membrane or sheeting material with a nominal thickness of 10 mils or less.

Film Thickness: The thickness of a membrane or coating that is expressed in mils (thousandths of an inch). See also Wet Film Thickness and Dry Film Thickness.

Fin: A sharp protrusion in a roof deck that can damage roof components.

Fine Mineral-Surfacing: A fine mineral material on the surface of roofing materials to prevent them from sticking to surfaces. 50% of this material has to pass through a sieve with holes that are 1/35" in size (#35 sieve).

Fishmouth: An opening along the exposed edge of an installed ply of felt caused by shifting the ply during installation. Repair these by making a slice along their entire length and feathering two plies of felt over the fishmouth for a minimum coverage of one foot all the way around.

Flaking: Occurs when a coating loses its cohesion.

Flame Retardant: A substance used to impede a material's tendency to burn or ignite.

Flame Spread: Per ASTM E 84, a measure of relative combustibility. The flame spread of a tested material is rated relative to asbestos cement board (flame spread = 0) and red oak flooring (flame spread = 100).

Flammability: The ability of a material to burn or ignite.

Flange: A projection edge of a roof component such as flashings, skylight frames, pre-manufactured curbs, etc. Usually refers to the part that sits on the roof surface.

Flash: v. To install flashing components.

Flash Point: The lowest temperature of a liquid material at which combustion will occur when air reaches its surface.

Flashing: Components used to seal the roof system at areas where the roof covering is interrupted or terminated. For example, pipes, curbs, walls, etc. all have special components that, when correctly installed, will help prevent moisture entry into the roof system or building.

Flashing Cement: A trowelable mixture of solvent-based bitumen and mineral stabilizers. Flashing cement that may contain asbestos stabilizers is categorized by ASTM standard D 2822-91 (1997) or for non-asbestos, ASTM standard D 4586-93. Flashing Cement is the term for Asphalt Roof Cement that can be used on vertical surfaces and has a high softening point, low ductility and conforms to the requirement of ASTM Specification D 312, Types II or III; or Specification D 449, Type III. See also Asphalt Roof Cement and Plastic Cement.

Flashing Collar: A flashing component used to seal soil pipe vents, hot stacks or other roof penetrations.

Flat Lock: A type of interlocking two separate metal panels by folding one panel over on top itself and the folding the other down under itself and then hooking the panels together.

Fleece: Mats or felts used as a membrane backer and composed of fibers.

Flood Coat: The surfacing layer of bitumen into which aggregate is embedded on an aggregate-surfaced built-up roof. A flood coat is applied at an approximate rate of 45 to 60 pounds per square (100 square feet).

Flood Test: A water test performed to determine the effectiveness of a roof covering.

Flow: To become fluid in character.

Fluid-Applied Elastomer: A liquid elastomeric material that cures to form a continuous waterproofing membrane.

FM: Short for Factory Mutual Research Corporation.

Foam Stop: The edge metal used to terminate Sprayed Polyurethane Foam.

Framed Opening: an structurally-framed opening in a roof of a building for use in installing large items such as HVAC units, skylights, or ventilators.

Froth Pack: A term used to describe small, disposable aerosol cans of SPF.


G-90: A coating weight for galvanized sheet metal,0.90 ounces of zinc per sq. ft., measured on both sides of the sheet.

Gable: A triangular-shaped portion of the endwall of abuilding directly under the sloping roof and above the Eave line.

Gable Roof: A roof configurationthat has gable ends.

Gable-On-Hip Roof: A roofconfiguration with hips coming up from the eave corners that terminate into agable roof.

Galvalume: Trade name for a protective coating composed of aluminum zinc.

Galvanic Action: A reaction between different metals in the presence of an electrolyte.

Galvanize: To coat with zinc.

Galvanized Steel: Steel that is coated with zinc to aid in corrosion resistance. Galvanized steel for use in roofing should be Hot-Dipped Galvanized with a G-90 coating.

Gambrel: A roof that has two different pitches.

Gauge: A standard of measurement. For instance the thickness of sheet metal or the diameter of wire. The thicker the wire or metal, the lower the gauge.

Geodesic Dome: A geodesic dome uses a pattern of self-bracing triangles in a pattern that gives maximum structural advantage, thus theoretically using the least material possible. (A "geodesic" line on a sphere is the shortest distance between any two points.) The first contemporary geodesic dome on record was designed by Walter Bauersfeld.

Girt: A horizontal beam place between support columns that is used for attaching wall cladding.

Glass Felt: (1)In the manufacturing of roofing materials - a sheet comprised of bonded glass fibers prior to being saturated with bitumen; (2) short for asphalt or coal tar saturated fiberglass felt membrane.

Glaze Coat: (1) The uppermost layer of asphalt on a smooth-surfaced built-up roof membrane, usually a reflective surfacing is installed over it; (2) A thin coat of bitumen applied to help protect the roof membrane when application of additional

felts or the flood coat and aggregate surfacing are delayed.

Grain: A unit of measure for the mass of moisture: a unit of weight equal to 0.002285 ounces or 0.036 dram.

Granule: A small aggregate, naturally or synthetically colored, used to surface cap sheets, shingles, and other granule-surfaced roof coverings.

Gravel: Aggregate consisting of rock fragments or pebbles.

Gravel Stop: A flanged, sheet metal edge flashing with an upward projection installed along the perimeter of a roof to stop the flow of bitumen over the edge.

Grout: A thin mortar used to fill cracks in masonry and tile.

Grout (Non-Shrink): A cementitious material used to partially fill penetration pockets (pitch pans). A pourable sealer is used afterward.

Gutter: A channel (usually sheet metal) installed along the downslope perimeter of a roof to convey runoff water from the roof to the drain leaders or downspouts.


Half Gable Roof: See Shed Roof.

Hand-Tabbing: Applying spots ofadhesive to shingle tabs.

Hatch: A unit used to provide access to a roof fromthe interior of a building.

Headlap: The distance that the topmost ply of roofingfelt overlaps the

undermostply or course.

Heat Seaming: See Heat Welding.

Heat Transfer: Thermal energy going from an area of higher temperature to an area of lower temperature by conduction, convection, or radiation.

Heat Welding: Fusing the seams of separate sections of roofing material together through the use of hot air or an open flame and pressure. Also known as heat seaming.

Hem: The edge created by folding metal back on itself. Metal is hemmed for safety and strength reasons.

Hip: The angle formed by the intersection of two sloping roof planes.

Hip Roof: A roof that rises by inclined planes on all sides of a building. The line where two adjacent sloping sides of a roof meet is called the Hip.

Hoist: A mechanical lifting device. A hoist can be hand or electrically operated.

Holiday: An area where a liquid-applied material is missing.

Honeycomb: Small voids left in concrete because the mortar failed to fill the spaces around the aggregate.

Hot: Slang for hot bitumen.

Humidity: The amount of water vapor in the air.

HVAC: Acronym for Heating, Ventilating, and Air Conditioning.

Hypalon: The trademark name for Chlorosulfonated Polyethylene (CSPE), which is a single-ply roofing material.


ICBO: International Conference of Building Officials,responsible for The Uniform Building Code.

Ice Dam: Ice formed at the transition from a warmsurface to a cold surface, such as along the overhang of a house. Thebuild-up of ice is the result of ice or snow melting on the roof area overthe warmer, living area of a building and then refreezing when it runs downand reaches the overhang.

Ignition Temperature: The minimumtemperature at which a material will combust.

Impact Resistance: A roofassembly's ability to withstand the impact from falling objects such as hail.

Impregnate: To saturate; in roofing, asphalt impregnated fiber glass roofing felts are fiber glass mats that have been completely permeated with asphalt bitumen.

Infrared Thermography: The use of an infrared camera to detect moisture in roof insulation.

Inorganic: Involving neither organic life nor the products of organic life; relating to compounds not containing hydrocarbon groups.

Insect Screen: Material used to inhibit an insects ability to enter a building through openings in a roof such as vents.

Insulation: Material used to help maintain a certain temperature in a building by reducing the flow of heat to and from that building. See also Thermal Insulation.

Intake Ventilation: The part of a ventilation system used to draw fresh air in. Usually vents installed in the soffit or along the eaves of a building.

Interlayment: A waterproof material usually installed between adjacent rows of wood shakes to help with the roof's waterproofing characteristics.

Interlocking Shingles: Shingles that lock together to provide wind resistance. See also T-Lock.

Internal Pressure: Atmospheric pressure inside a structure that correlates to the number and location of openings and air leaks.

Inverted Roof Membrane Assembly (IRMA®): A variation of the "Protected Membrane Roof Assembly" in which Styrofoam® brand insulation is used. IRMA® and Styrofoam® are registered trademarks of the Dow Chemical Company.

IRWC: Institute of Roofing and Waterproofing Consultants

ISANTA: International Staple, Nail & Tool Association

Isocyanate: A highly reactive organic chemical containing one or more Isocyanate groups. A basic component in Sprayed Polyurethane Foam systems and some polyurethane coating systems.


Jack: See Roof Jack.

Joint Tape: Tape used to seal joints between insulation boards.

Joist: Any of the parallel horizontal beams set from wall to wall to support the boards of a floor, ceiling or roof of a building.


Knee Cap: Sheet metal trim that fits over a panel rib after it has been cut and bent.


Laitance: An accumulation of fine, powdery aggregateparticles on fresh cement caused by the upward movement of water; indicatesthat too much water was used in the mix resulting in poor surface adhesionfor a waterproofing layer.

Laminated Shingles: SeeDimensional Shingles or Architectural Shingles.

Lap: The part of the roofing material that overlapsa section of adjacent material.

Lap Cement: Asphalt-based roofcement used to adhere overlapping plies of asphalt roll roofing.

Lap Seam: Where two material that overlap are sealed together.

Lead: Metal used for flashing material.

Leader Head: A component used to direct water from a through-wall scupper to a downspout. Also known as a Collector Head.

Leader Pipe: A conduit for carrying water from a gutter, scupper, drop outlet or other drainage unit from roof to ground level. Also known as Downspout.

Lift: The rise in Sprayed Polyurethane Foam resulting from a pass.

Live Loads: Temporary items on a roof such as equipment, people, snow, etc. which the roof must be designed to support.

Loose-Laid Roof Membranes: Roofing material attached only at the perimeter and at penetrations and held in place by ballast, pavers, or other materials.


Mansard: (1) A steep-sloped roof located at theperimeter of a building and usually used for decorative purposes. (2) Theupper story formed by the lower slope of a mansard roof.

Mansard Roof: A steeper roof thatterminates into a lower sloped roof at its high point.

Masonry: Refers to bricks, concrete, or concrete blocks.

Mastic: See Asphalt Roof Cement.

Mat: A thin layer of woven, non-woven, or knitted fiber used to reinforce a material.

Material Safety Data Sheets (MSDS): Written descriptions of the chemicals in a product provided by the product's manufacturer. MSDS also contain other information such as emergency procedures and safe handling.

MBMA: Metal Building Manufacturers Association

MCA: Metal Construction Association

Mechanical Damage: Damage to a roof by means of items puncturing or otherwise unnecessarily penetrating the roof system or any of its components. Screws or nails stuck in the roof and heel marks along base flashings are examples of mechanical damage.

Mechanical Fasteners: Devices such as screws, plates, battens, nails, or other materials that are used to secure roofing materials.

Membrane: The portion of the roofing system that serves as the waterproofing material. Can be composed of one material or several materials laminated together.

Metal Flashing: Roof components made from sheet metal that are used to terminate the roofing membrane or material along roof edges. Metal flashings are also used in the field of the roof around penetrations.

Meter: Metric unit of length measurement equal to 39.37 inches.

Mil: A unit of measure equal to 0.001 inches (1/1000 in.) used to indicate the thickness of a roofing membrane.

Mildew: A superficial coating or discoloration of organic materials caused by fungi, especially under damp conditions.

Millimeter: Metric unit of measure equal to one thousandth (0.001) of a meter, or 0.03937 inches.

MIMA: Mineral Insulation Manufacturers Association

Mineral Fiber: Inorganic fibers of glass or rock.

Mineral Granules: See Granules.

Mineral-Surfaced Roofing: Roofing materials with a top surface consisting of mineral granules.

Miter: The joint made by two diagonally cut pieces put together.

Model Codes: A group of codes and standards accepted by more than one of the Building Code regulatory agencies such as SBCCI, BOCA, and ICBO

Modified Bitumen: a bitumen modified by one or more polymers such as Atactic Polypropylene (APP), styrene butadiene styrene (SBS).

Moisture Relief Vent: A vent installed through the roofing membrane to relieve moisture vapor pressure that has been trapped within the roofing system.

Moisture Scan: A survey of a roof specifically to detect the amount of moisture present in the roof system. Devices used in moisture surveys can be capacitance meters, infrared cameras, and nuclear scanners. Infrared scans can be done from the air or on the surface of the roof. Capacitance and nuclear scans are done on the roof surface. It is argued that the most accurate scans are done from the surface of the roof with the most accurate of these being nuclear scans.

Mole Run: A term used to describe a ridge in a roof membrane that is not the result of improper deck or insulation joints.

Monolithic: Used to describe something without seams; formed from a single material.

Monomer: A simple molecule that can combine with other to form a polymer.

Mop-and-Flop: A roofers' term where the back side of a roofing material is mopped, then the piece is turned over and set in place.

Mopping: To apply hot asphalt or coat tar using a hand mop or mechanical applicator.

Mud Cracking: Surface cracking of a material that looks similar to dried, cracked mud.

Multiple Coats: More than one layer of coating applied to a substrate.


NAHB: National Association of Home Builders

Nailer: A piece of lumber, preferably treated, that issecured to the deck, walls, or to premanufactured curbs. Nailers are used toreceive fasteners for roof membranes. Generally, nailers are installedwherever it is necessary to secure base flashings and edge metal. Also see Blocking.

Nailing Pattern: Refers to aspecific method or pattern at which nails are applied. For instance, anailing pattern for base sheets on plywood roof decks can be "Nine andEighteen". This means one row of nails on the outside edge of the sheetset at nine inches (9") on center, and two rows in the center of thesheet, each set at eighteen inches (18") on center.

Neoprene: A synthetic rubber produced by polymerization of Chloroprene for use in liquid-applied and sheet-applied elastomeric roofing.

Nesting: To overlay existing shingles with new shingles and butt the top edge of the new shingle up against the bottom edge of the existing shingles.

Net Free Vent Area: The area permitting unrestricted air flow.

Newton (N): In the meter-kilogram-second system, the unit of force required to accelerate a mass of one kilogram one meter per second per second (s².)

NICA: National Insulation Contractors Association

Night Seal: To temporarily seal the edge of a roof membrane in order to protect it from moisture entry. A.K.A. Night Tie-Off and Water Cut-Off.

Ninety-Pound: Granule-surfaced or fiber glass or organic felt roll roofing that has a mass of approximately 90 pounds per 100 square feet.

NIST: National Institute of Standards and Technology

Noble: In reference to metal, inert or inactive.

No-Cutout Shingle: A shingle made of one solid strip of material.

Non-Breathing Membrane: A membrane that does not permit water vapor or air to permeate it.

Non-Flammable: Material with no measurable flash point.

Non-Friable: Refers to a material's inability to be crushed or pulverized into a powder.

Non-Volatile Content: The portion of a material that will not evaporate.

Non-Vulcanized Material: A material that retains its thermoplastic properties throughout its service life.

Nonwoven: Random arrangement of the reinforcement fibers of a scrim sheet or mat.

Nosing: Metal flashing bent at a 90º angle and is installed around roof perimeters, curbs, platforms, etc. in order to protect the edge of the roofing system. Nosing should not be used in place of drip edge. To see the difference in the two.

NRCA: National Roofing Contractors Association.

NTRMA: National Tile Roofing Manufacturers Association


Off-Ratio Foam: SPF where the 1 to 1ratio of the A and B components has been compromised and which results in alower quality material.

Open Time: The time after anadhesive has been applied and permitted to cure when the two surfaces can bebonded.

Open Valley: A valley where bothsides of the roof are trimmed back from the centerline to expose the valleyflashing material beneath.

Orange Peel Surface Texture: A surface with a texture comparable to the skin of an orange upon which a protective coating may be applied.

Organic: Formed from hydrocarbons.

Organic Felt: An asphalt roofing base material manufactured from cellulose fibers.

Organic Shingle: An asphalt shingle reinforced with organic material manufactured from cellulose fibers.

ORNL: Oak Ridge National Laboratory

OSB: Oriented Strand Board - Often used as roof sheathing in place of plywood.<picture>

Overlay: See Re-Cover.

Overspray: The loss of spray particles (from coatings, SPF, etc.) in the air.


Pallet: A platform, generally from wood, used to holdmaterials.

Pan: (1) The concave piece of "Pan andCover" tile whose rounded surface touches the top side of the roofsubstrate. (2) The flat part of a roofing panel located between the ribs.

Pan Flashing: A sheet metal flashingthat covers an equipment platform and is designed to counter flash the baseflashings surrounding the platform.

Parapet Wall: That part of a perimeterwall that extends above the surface of the roof.

Pass: The term used to describe the application of one layer of Spray Polyurethane Foam (SPF). The speed of a pass will determine foam thickness.

Pass Line: The distinct line formed between two passes of SPF. This line is the top skin of the bottom pass of the SPF.

Penetration: Any object that pierces the surface of the roof.

Percent Elongation: The maximum amount that a material can be lengthened or stretched before breaking; expressed as a percentage of the original length of material tested.

Perlite: A natural volcanic glass having distinctive concentric cracks and a relatively high water content.. Perlite in a fluffy heat expanded form is used in lightweight insulating concrete, fire-resistant rigid insulation board (R = 2.78 per inch) and potting soil.

Perm: A unit of water vapor transmission, defined as one grain of water vapor per square foot per hour per inch of mercury (Hg) pressure difference (1 inch of mercury = 0.491 psi).

Permeability: The rate of flow of a liquid or gas through a porous material.

pH: A measure of the acidity or alkalinity of a solution, numerically equal to 7 for neutral solutions, increasing with increasing alkalinity and decreasing with increasing acidity. The pH scale commonly in use ranges from 0 to 14.

Phasing: Installing roof system components in separate time intervals. For instance, installing a base sheet, and then two plies of roofing one day, and coming back and installing the remaining two plies one or more days later. It is generally not considered Phasing if the surfacing is applied at a later date.

Picture Framing: Rectangular patterns seen in a roof that are created by buckles or ridges in the roof system or sumps in the substrate.

PIMA: Polyisocyanurate Insulation Manufacturers Association

Pinhole: A small hole in a coating, foil, membrane, or other roofing material.

Pipe Boot: A prefabricated flashing piece used to flash around circular pipe penetrations. Also known as a Roof Jack.

Pitch: Term used to describe Roof Slope and also short for Coal Tar Pitch.

Pitch Pocket (A.K.A. Pitch Pan): A flanged piece of flashing material placed around irregularly shaped roof penetrations and filled with grout and a pourable sealer to seal around the penetration in order to seal it from against moisture entry. Pitch pockets are a good source of leaks and should be avoided if possible. For an example on how to properly fill a pitch pocket.

Pittsburgh Lock Seam: A method of interlocking two separate pieces of metal.

Plastic Cement: A term used to describe Type I asphalt roof cement. Plastic cement should not be used on vertical surfaces. See also Asphalt Roof Cement and Flashing Cement.

Plastic Film: A flexible sheet made by the extrusion of thermoplastic resins.

Plasticizers: Material incorporated into rubber and plastic in order to increase their flexibility and workability.

Plenum: A space or enclosure in which air or other gas is at a pressure greater than that of the outside atmosphere.

Ply: A layer of felt or other reinforcement material in a roof system.

PMR: See Protected Membrane Roof.

Polyester: Any of numerous synthetic polymers produced chiefly by reaction of dibasic acids with Dihydric alcohols and used primarily as light, strong, weather-resistant resins. In roofing, polyester is used to reinforce fabrics.

Polymer: Any of numerous natural and synthetic compounds of usually high molecular weight consisting of up to millions of repeated linked units, each a relatively light and simple molecule.

Polymer Modified Bitumen: See Modified Bitumen.

Polymeric Methylene Diphenyl Diisocyanate (PMDI): The "A" component in SPF; when mixed with "B", it forms polyurethane. PMDI is an organic chemical compound having two reactive Isocyanate (-N=C=O) groups.

Polymerization: The combining of monomers to produce polymers.

Polypropylene: Any of various thermoplastic resins that are polymers of propylene. They are hard and tough, and are used to make molded articles and fibers.

Polyvinyl Chloride (PVC): A thermoplastic polymer that can be compounded into flexible and rigid forms through the use of plasticizers, stabilizers, fillers, and other modifiers; rigid forms are used in pipes; flexible forms are used in the manufacture of sheeting and roof membrane materials.

Ponding: The accumulation of water at low-lying areas on a roof.

Pop Rivet: A small metal pin having a head on one end, inserted through aligned holes in pieces of light gauge metal to be joined and then the head is expanded to join the metal.

Popcorn Surface Texture: A coarse surface texture of SPF considered unacceptable for coatings.

Positive Drainage: The drainage condition of a roof where all water is gone from the roof surface within forty-eight hours of precipitation during normal drying conditions.

Pot Life: The period of time during which a material with multiple ingredients can be applied or administered after being mixed together.

Pourable Sealer: A type of sealant that is initially in liquid form commonly used in conjunction with pitch pans to form a water-tight barrier around penetrations that are difficult to flash.

Press Brake: A mechanical device used to form sheet metal into desired shapes and profiles.

Primer: A material that is applied to a surface in order to increase that surface's ability to adhere to or work in conjunction with a subsequently applied material.

Proportioner: A pumping unit comprised of two (2) positive displacement pumps that is designed to dispense two (2) components at a precise ratio. Used in SPF and plural component coating applications.

Protected Membrane Roof (PMR): A roof assembly in which the insulation and ballast are placed on top of the membrane component. Commonly referred to as an "inverted roof assembly."

Psychrometer: An instrument that uses the difference in readings between two thermometers, one having a wet bulb and the other having a dry bulb, to measure the moisture content or relative humidity of air.

Puncture Resistance: The ability of a material to withstand being pierced by a sharp object.

Purlin: Horizontal secondary structural member used to transfer loads from the primary structural members.

PVC: Polyvinyl Chloride.


Radian Barrier: a reflective surfacethat intercepts the flow of radiant energy to or from a building component.

Raggle: A groove that is cut into the side of avertical surface such as a wall or chimney that is used to insert a flashingelement such as a reglet or counterflashing.

Rake: The sloped perimeter edge of a roof that runsfrom the eaves to the ridge. The rake is usually perpendicular to the eavesand ridge.

Rake-Starter: A starter strip placedalong rake edges for use in asphalt shingle roofing. See also Bleeder Strip.

RCI: Roof Consultants Institute

RCMA: Roof Coatings Manufacturers Association

RDCA: Roof Deck Contractors Association

Re-Cover (Overlay): The installation of a new roof system over an existing system without removing an existing system. For some hints on recovers..

Reglet: A receiver, usually sheet metal, that counterflashings are attached to. Reglets can be surface-mounted, set in a raggle, or be part of the wall assembly.

Reinforced Membrane: A roofing membrane that has been strengthened by adding polyester scrims or mats, glass fibers or other material.

Relative Humidity: The amount of water vapor in the air compared to the amount of water vapor that the air can hold at a given temperature. For example, if the relative humidity is 50 percent, then the amount of water vapor in the air is half of what the air could actually hold at that temperature.

Remove and Reinstall: To remove a component and reuse that component by reinstalling it.

Remove and Replace: To remove a component and replace it with a new component of the same or similar type.

Reroofing: The procedure of installing a new roof system.

Resin: The "B" component in SPF that is mixed with the "A" component in order to form polyurethane. Resin contains a catalyst, fire retardants, a blowing agent, Polyol, and a surface active agent.

Ridge: The line where two planes of roof intersect, forming the highest point on the roof that runs the entire length of the roof.

Ridge Cap: Material applied over the ridge or hip of a roof.

Ridge Course: The final course of roofing applied that covers the area where two or more roof planes intersect.

Ridge Vent: An exhaust venting device located at the ridge of a roof that works in conjunction with a starter or under eave soffit vent and is used to ventilate attics. Ridge vents and their cooperative starter or soffit vents should be installed at a 1:1 ratio in order to function properly.

Ridging: The formation of a Buckle.

RIEI: Roofing Industry Educational Institute

RMA: Rubber Manufacturers Association

Roll Goods: The term used for all roofing materials that come in rolls.

Roof Assembly: A term used to describe all of the roof components including structural roof deck.

Roof Cement: See Asphalt Roof Cement and Coal Tar Roof Cement.

Roof Covering: The outermost reinforced layer of the roof assembly. In BUR it's the multiple-ply membrane, in Thermoplastic roof systems it's the thermoplastic sheet, etc.

Roof Curb: A frame used to structurally mount rooftop equipment such as HVAC units, exhaust fans, skylight, etc.; may be pre-constructed or constructed on site.

Roofer: An individual who installs roof systems and materials.

Roof Jack: (1) A steel bracket fastened to the roof that is used to support toe boards. (2) A term used to describe a Pipe Boot or Flashing Collar.

Roof Overhang: That portion of the roof that extends beyond the exterior wall line of the building.

Roof Seamer: (1) A mechanical device used to crimp metal roof panels and make the seams watertight. (2) A machine used to weld membrane laps of PVC (Thermoplastic) roofing material.

Roof Slope: The angle made by the roof surface plane with the horizontal plane and expressed as the amount of vertical rise for every twelve inch (12") horizontal run. For instance, a roof that rises four inches (4") for every twelve inch (12") horizontal run, is expressed as having a "four in twelve" slope; often written as "4:12." Expressed as a percentage, the slope would be 33%, which is equal to 4 divided by 12. Also known as the Pitch of a roof. For more information on Roof Slope.

Roof System: Multiple roof components assembled to provide waterproofing (and sometimes insulating) capabilities for a structure.

Rosin: Non-asphaltic material used as slip sheets and sheathing paper in roof systems. Also referred to Rosin Paper and Rosin-Sized Sheathing Paper.

Run: The horizontal dimension of a slope.

Rust Blush: Early stage of rust indicated by an orange or reddish color.


Saddle: (1) A type of flashing usually used inconjunction with step, counter, and apron flashings on steep slope roofsystems. (2) A small, somewhat pyramid-shaped figure constructed in betweensump drains that is used to direct run-off water toward the sump drains.

Sag: Settling or drooping of base flashings thathave not been properly secured to a surface.

Saturated Felt: Felt that has beensaturated with bitumen.

SBCCI: Southern Building Code Congress International,Inc.

SBS: Styrene Butadiene Styrene.

Scarfed: Shaped by grinding.

Screeding: Bringing the surface of concrete to the final, desired look and finish by removing any excess or unwanted material.

Screen or Screen Wall: See Equipment Screen.

Scrim: Woven or nonwoven material used to reinforce membranes; it is usually laminated or coated to produce the membrane.

Scuttle: A unit that provides access to the roof from the interior of the building. See also Hatch.

SDI: Steel Deck Institute

Sealant: Generic term for a multitude of materials used to seal joints or junctures against moisture or weather.

Sealer: Coating designed to prevent bleedout or bleed-through.

Seam: A line, ridge, or groove formed from fitting, joining, or lapping two sections together.

Self-Adhering Membrane: A type of membrane whose bottom surface will stick or adhere to a substrate without the use of an additional adhesive material.

Self-Drilling Screw: A screw with a small drill-bit like tip that will drill its own hole and eliminate the need to pre-drill a hole.

Self-Sealing Shingle: Asphalt shingles with adhesive strips that will soften and stick to the following course of shingles when heated by the sun; used to help against wind uplift.

Self-Tapping Screws: Fasteners that make screw thread receivers when screwed into a hole.

Self-Vulcanizing Membrane: Membrane that is initially thermoplastic in nature but that cures after installation.

Selvage Edge: That portion of a granule-surfaced membrane that is designed to be overlapped by the following membrane course; usually two, four, or nineteen inches in width.

Shark Fin: A curled corner or lap in a membrane.

Shed Roof: A roof with only one sloping plane. Also known as Half Gable.

Shelf Life: The length of time between the manufacture of a material and when the material is no longer suitable for use.

Shiner: Term used to describe an exposed nail; one that was not covered by the following course of roofing material.

Shingle: (1) A single piece of prepared roofing material, either asphalt or wood, for use in steep slope roof systems. (2) To install a wood or asphalt shingle roof system.

Shingle Fashion: Refers to the way courses of like materials are overlapped in order to have multiple layer coverage.

Shrinkage: The process of shrinking; depreciation in size.

Shrinkage Crack: A crack caused by material shrinkage. May be the result of thermal expansion/contraction, material failure, or cure.

SI: The international system of weights and measures (metric system). Système International [d'Unit[eacute]s]

Side Lap: The longitudinal overlap of neighboring materials.

Siding: Exterior wall finish materials applied to the outside of a structure.

Sill: The bottom framing member of a door or window opening.

Sill Flashing: Flashing material(s) used to waterproof the bottom framing member of a door or window opening.

Single Coverage: One layer of roofing material.

Single-Lock Standing Seam: A standing seam system with one overlapping interlock between two seam panels.

Single-Ply Membranes: Roofing membranes that are applied in one layer. Thermoplastic and thermoset membranes are usually Single-Ply Membranes. Single-Ply membranes come in five basic types: (1) Ballasted, (2) Fully-Adhered, (3) Mechanically-Fastened, (4) Partially-Adhered, and (5) Self-Adhered. Seams of Single-Ply Membranes can be heat welded, solvent welded, and adhered using seam tape or other adhesives.

Single-Ply Roofing: Roofing systems where the principal component consists of a single-ply membrane.

Skylight: A transparent or translucent item that is designed to admit light and set over a curbed opening in the roof.

Slag: Residue from blast furnaces that is sometimes used for the surfacing on aggregate-surfaced built-up roof systems.

Slate: A fine-grained metamorphic rock that splits into thin, smooth-surfaced layers used in steep slope roofing applications.

Slating Hook: A hook-shaped device used to secure roofing slate.

Slip Sheet: Sheeting material placed between roofing components to prevent those components from adhering to one another or to prevent material damage due to component incompatibility. Slip Sheets may be polyethylene, rosin-sized sheathing paper, or other material.

Slit Sample: A cut made in SPF roofing to measure coating thickness. The cut should be about 1.5" long by ¾" deep by ½" wide.

Slope: The angle of incline of a roof expressed as a percent or as a ratio of rise to run. See Roof Slope.

SMACNA: Sheet Metal and Air Conditioning Contractors National Association

Smooth Surface Texture: In SPF roofing, a relatively smooth surfaced texture that is considered ideal for receiving the base coating.

Smooth Surfaced Roof: A roof with no surfacing or with a smooth surfacing such as emulsion and/or a reflective coating.

Snow Guard: Devices secured to the roof to prevent snow and ice from sliding off of a roof.

Snow Load: A roof load resulting from snowfall. Snow load is a major structural consideration when roofs are designed in areas that receive heavy snow.

Soffit: The underside of a roof overhang.

Soffit Vent: An intake ventilation device located in the soffit. An exhaust vent should be installed on or near the ridge of the roof to work in conjunction with the soffit vent in order to properly ventilate the attic space. The ratio of intake vent area to exhaust vent area should be 1:1.

Softening Point: The temperature at which bitumen will begin to Flow.

Softening Point Drift: A change in the softening point of bitumen. See also Fallback

Soil Pipe: A pipe that penetrates a roof and is used to vent a building's plumbing.

Solder: Any of various fusible alloys, usually tin and lead, used to join metallic parts.

Solid Mopping: To continuously apply hot asphalt or coal tar leaving no areas without bitumen.

Solvent: (1) A liquid capable of dissolving other substances such as bitumen. (2) A liquid that is part of a substance and is used to make that substance easier to work with. Once applied, the solvent evaporates and leaves the working characteristics of the substance. Examples are solvent-based adhesives and solvent-based mastics.

Solvent Weld: To weld materials using a liquid solvent.

Spall: A chip, fragment, or flake from concrete or masonry.

Special Steep Asphalt: A roofing asphalt conforming to the requirements of ASTM Specification D 312, Type IV. This asphalt can be used on roofs with slopes up to 6 in 12 (50%).

Specification: Written requirements for a construction project; contains but is not limited to the following: the scope of work, methods of construction, and materials.

SPF: Sprayed Polyurethane Foam.

SPF Compounds: Refers to the Isocyanate and resin components used to make polyurethane foam.

SPI: The Society of the Plastics Industry

SPI/SPFD: The Society of the Plastics Industry/Sprayed Polyurethane Foam Division

Splash Guard: A fabricated metal pan or masonry block that is placed below a leader pipe or downspout and is used to help protect the roof membrane on a lower roof level or to prevent soil erosion when placed on the ground.

Splice: To join by overlapping along ends.

Splice Plate: A metal plate placed beneath the joint between two pieces of metal.

Splice Tape: A self-adhering (usually double-sided) tape used for splicing membrane materials.

Split: The separation of a material resulting from tensile forces.

Sprayed Polyurethane Foam (SPF): A monolithic sprayed-on roofing material with a high R-value; formed when isocyanate ("A" component) and resin ("B" component) are mixed at a 1:1 ratio.

SPRI: Single Ply Roofing Institute

Sprinkle Mopping: To scatter hot bitumen over a surface.

Spud: To remove the top surfacing of a roof by scraping it with special tools called spud bars or power spudders.

Spud Bar: A long-handle tool with a stiff flat blade on one end (usually 4" or 6" wide) that is used to scrape and remove the top surfacing of a roof down to the membrane.

Spunbond: Describes nonwoven fabrics made from continuously bonded fibers.

Spunlaced: Describes nonwoven fabrics that have the fibers intertwined by water-jet method.

Square: (1) 100 square feet of roof area (9.29 m2) in the USA. (2) 10 square meters (107.639 ft.2) of roof area using the metric system of weights and measures.

Stack Effect: The occurrence where air escapes through opening in the upper part of a building and is replaced with outside air which enters through an opening lower down. In roofing, the Stack Effect helps create proper air flow for attic or roofspace ventilation. The Stack Effect will be affected by atmospheric conditions such as temperature and wind.

Stainless Steel: A highly corrosion resistant steel alloy containing either chromium, nickel, or copper.

Stair Step: The diagonal method of laying shingles.

Standing Seam: A type of metal roof system where the longitudinal seams on adjacent panels are turned up, overlapped and folded in various ways in order to prevent moisture entry and interlock the panels.

Starter Course: The primary course of roofing materials. The Starter course is installed along the downslope perimeter edge and usually covered by the first course of roofing.

Starter Plies: Felt or ply sheets that are cut into widths that are proportionate to the reciprocal of the number of plies being installed. For instance, with a three-ply built-up roof, the first starter ply would be one-third of the roll width, the second two-thirds of the roll width installed over it, and then a full ply over those.

Starter Strip: Strips of shingles (usually 3-Tab shingles with the tabs cut off) or roll roofing material that is laid along the eave line of the roof prior to the application of the first course of shingles. The starter strip is used to fill in the gaps created by shingle cutouts and joints.

Static Load: Roof loads that do not move such as HVAC units.

Steep Asphalt: A roofing asphalt conforming to the requirements of ASTM Specification D 312, Type III. This asphalt can be used on roofs with slopes up to 3 in 12 (25%).

Steep-Slope Roof: A roof with a slope exceeding 3 in 12 (25%). Deemed appropriate to receive water-shedding type roofing materials such as asphalt shingles, wood shakes and shingles, concrete or clay tile, etc.

Steep-Slope Roofing Materials: Roofing materials that depend on their water-shedding capabilities to keep moisture from entering a building. These materials are generally installed on roofs with slopes that equal or exceed 3" in 12" (25%).

Steeple: A tall tower forming the superstructure of a building, such as a church or temple, and usually surmounted by a spire.

Step Flashing: Pieces of metal or other material that are used to flash roof projections such as chimneys, walls, curbs, etc. The pieces are installed between each course of roofing and generally have a vertical flange equal in length to that of the horizontal flange.

Strapping: Installing roofing felts so that they run parallel with the slope. Not a recommended installation method for slopes that are 1:12 or less.

Strawberry: See Tar Boil.

Straw Nail: Long-shanked nails used to fasten tile along hips and ridges.

Strip Flashing: Pieces of membrane material that are used to flash metal flashing flanges such as gravel stop. Also referred to as Stripping.

Strip Mopping: Hot bitumen applied in parallel bands.

Strip Shingles: Asphalt shingles that are manufactured in strips.

Styrene: A colorless oily liquid, C6H5CH:CH2, the monomer for polystyrene.

Styrene Butadiene Styrene (SBS): The modifying agent used in SBS modified asphalt roofing materials that gives the material a rubber like quality.

Substrate: The surface that the roof is installed upon.

Sump: A depression around roof drains and scuppers to help promote roof drainage.

Surface Erosion: The effect on a surface after being worn away from abrasion or weathering.

Surface Texture: The final appearance and quality of an SPF surface. SPF surface textures will be one of the following: Orange Peel Surface Texture, Coarse Orange Peel Surface Texture, Smooth Surface Texture, Verge of Popcorn Surface Texture, Popcorn Surface Texture, and Tree-Bark Surfaced Texture.

Surfacing: The top-most layer of the roof system designed to protect the system from damage.

Surfactant: Short for "surface active agent." A soluble compound that reduces the surface tension of liquids, or reduces interfacial tension between two liquids or a liquid and a solid having cationic (positive charge), anionic (negative charge), or non-ionic (no charge) nature. The ingredient in SPF that controls the cell size.

SWRI: Sealant, Waterproofing and Restoration Institute


Tab: The portion of an asphalt shingle that isoutlined by the cutouts.

Tapered Edge Strip: Taperedinsulation strip used to ease transitions from one substrate elevation toanother and to provide slope along roof perimeters.

Tape: See Joint Tape and Splice Tape.

Tar (ASTM DEFINITION): A brown orblack bituminous material, liquid or semi-solid in consistency, in which thepredominating constituents are bitumens obtained as condensates in theprocessing of coal, petroleum, oil-shale, wood, or other organic materials.

Tar Boil: A small bubble found in the flood coat of an aggregate-surfaced built-up roof; usually the result of trapped moisture vapor. Tar Boils are also known as blueberries or blackberries.

Tear-Off: To remove a roof system down to the structural substrate.

Tear Resistance: A material's ability to withstand tearing. The test is performed by placing stress on an area of the material where a flaw is located. Tear Resistance is expressed in psi per inch width or kilonewton per meter width.

Tear Strength: The strength necessary to tear a material.

Tensile Strength: The amount of longitudinal pulling stress that a material can withstand before being pulled apart.

Termination: The sealed edges of a roof membrane.

Termination Bar (Term.' Bar): A bar, usually metal or vinyl, used to seal and anchor the free edges of a roof membrane.

Terne: Sheet iron or steel plated with an alloy of three or four parts of lead to one part of tin, used as a roofing material.

Terra Cotta: A semifired ceramic clay used in building construction.

Thatch Roof: A roof covering made with straw, palms, reeds or other natural growths that are bound together in order to shed water.

Thermal Barrier: Material used in conjunction with polyurethane foam that is designed to inhibit the rise in temperature of the foam during a fire in order to delay the foam's involvement in the fire. Time ratings for thermal barriers should exceed 15 minutes.

Thermal Conductance (C): A constant, equal to a material's k-value (Thermal Conductivity) divided by the material's thickness in inches; used often for materials of composite construction such as insulation. For more information.

Thermal Conductivity (k): The heat energy that will be transmitted by conduction through 1 square foot of 1inch thick homogeneous material in 1 hour when there is a difference of 1 degree Fahrenheit perpendicularly across the two surfaces of the material. The higher the k-value, the lower the R-value. Materials with high k-values are good heat conductors, and conversely. For more information.

Thermal Insulation: A material used to reduce heat flow.

Thermal Movement: Movement of a material resulting from temperature changes.

Thermal Resistance (R): The measure of a material's ability to resist heat flow. The formula for Thermal Resistance is R = L / k where (L) is the material's thickness and (k) is the material's Thermal Conductivity constant. The higher a material's R-value, the better it insulates, and conversely. For more information.

Thermal Shock: The damage to a roof resulting from expansion and contraction which are the result of sudden extreme temperature changes. Thermal Shock often occurs when a cold rain shower suddenly cools a roof during a hot day.

Thermal Stress: Stress to a roof system or component caused by expansion and / or contraction from temperature change.

Thermoplastic: (1) adjective Becoming soft when heated and hard when cooled. (2)noun A thermoplastic resin, such as polystyrene or polyethylene.

Thermoset: A material that cannot be reshaped or formed by heating. EPDM and Butyl are thermosets.

Thinners: Liquids that are used to reduce a material's viscosity when mixed but that evaporates during cure.

Thixotropy: Property of certain materials which liquefy when they are subjected to vibratory forces such as simple stirring or shaking and then solidify when left standing.

Throat: (1) The cutout of a shingle. (2) The narrowing passage located between a fireplace and smoke chamber or flue.

Through-Wall Flashing: A material that extends through a wall and is used to direct water entering a wall cavity to the exterior of the structure.

Tie-In: The joining of two different roof systems.

Tie-Off: A watertight seal used to terminate roof membranes at system adjuncts, terminations, flashings, or substrates. Can be temporary (see Night Seal) or permanent.

TIMA: Thermal Insulation Manufacturers Association

Toggle Bolt: A bolt with a separate toggle end that can be flattened to fit through a pre-drilled hole and that springs outward to provide securement when the bolt is tightened.

Tongue and Groove: Premanufactured materials with a convex "tongue" on one side and a concave "groove" on the other so that pieces of material can be joined together by placing the tongue of one piece into the groove of an adjacent piece so that the pieces fit more securely together.

Torque: Force applied to an object, particularly, to screw a mechanical fastener into a roof deck or substrate.

TPA: Tri-Polymer Alloy.

Traffic: Any rooftop activity that can potentially damage the roof surface.

Transverse Seam: The joint between the top of one metal roof panel and the bottom of the next panel, which runs perpendicular to the roof slope.

Treebark Surface Texture: An SPF surface deemed unacceptable for coating. This surface texture has deep valleys and is similar in appearance to rough tree bark.

Tuck Pointing: To remove old and deteriorated mortar from between masonry blocks and replace it with new mortar.


U-Value: The overall coefficient of heat transfer of anassembly measured in BTUs per square foot, per degrees Fahrenheit differencein temperature per hour.

UBC: Uniform Building Code.

UL: Underwriters Laboratories, Inc.

UL Label: A label that has been stamped on certainmaterials by authority of Underwriters Laboratories, Inc. indicating that thematerial has met certain performance criteria.

Ultraviolet Light (UV): A form of luminous energy occupying a position in the spectrum of sunlight beyond the violet, and having wavelengths that do not enter the visible spectrum. UV rays accelerate deterioration of roof materials. Hence, the need for protective coatings.

Underlayment: A material installed over the roof deck prior to the application of the primary roof covering. Usually consists of fifteen (15#) or thirty (30#) pound organic felt but can also be self-adhering such as an ice and water protection membrane.

Underwriters Laboratories (UL): A non-profit agency which functions as the testing arm of the National Board of Fire Underwriters. It maintains laboratories for the examination and testing of various devices, systems, and materials to determine their safety against the hazards of fire, wind, and accidents.

Uplift: See Wind Uplift.

Upside Down Roof: See Protected Membrane Roof.


Valley: The internal intersection of two sloping roofplanes that runs from the eaves to the ridge. This intersection collects themost water run-off. See Open Valley, Closed-Cut Valley, and Woven Valley.

Vapor Migration: The naturalmovement of water vapor from regions of higher vapor pressure to regions oflower vapor pressure.

Vapor Pressure: The pressure at which aliquid and its vapor are in equilibrium at a definite temperature.

Vapor Retarder: A material used torestrict the passage of water vapor through a roof assembly.

Veneer: Any of the thin layers of wood glued together to make plywood.

Vent: An opening or device used to permit air or vapors to exit an enclosed structure.

Ventilation Short Circuit: The disruption of air flow in an intake-exhaust ventilation system. For instance, if vents such as turbine vents or gable vents are placed in between the intake vents and exhaust vents (such as soffit and ridge vents) then the draw created by the Stack Effect will be disrupted and the ventilation system will be much less effective.

Ventilator: A device that circulates fresh air and expels stale air.

Verge of Popcorn Texture: A rough surface texture of Sprayed Polyurethane Foam generally considered unsuitable to receive a base coating. Nodules on this surface are larger than the valleys and an additional 50% or more of coating material is necessary to properly cover and protect the surface. Photos?

Vermiculite: One off a group of micaceous hydrated silicate minerals related to the chlorites and used in lightweight insulating concrete.

Viscosity: The resistance of a material to heat flow.

Viscous: Having a fairly high resistance to heat flow.

Void: An open space or a break in continuity; a gap.

Volatile: That which readily vaporizes; evaporates quickly.

Vulcanize: To improve the strength, resiliency, and freedom from stickiness and odor of rubber, for example, by combining with sulfur or other additives in the presence of heat and pressure.


Water Absorption: The increase in weight of a test specimen expressed as a percentage of its dry weight after being immersed in water for a specified time at a given temperature.

Water Cure: To control the rate of cure of materials such as concrete by spraying a fine mist of water on the surface.

Water Cut-off: See Night Tie-Off.

Water Guard: A turned up edge on valley metal or continuous wall flashing; used to prevent water migration under the roof system.

Water Stop: Material placed over a joint and used to prevent water entry.

Waterproof: Being resistant to moisture infiltration.

Waterproofing: The treatment of a surface or structure in order to prevent the passage of water under hydrostatic pressure.

Water Trough: The area in a valley where water runs. Usually referred to with open valley configurations.

Weather: To undergo degradation in quality and appearance which is caused by exposure to the sun, wind, rain, etc.

Weep Holes: Small holes used to permit moisture to drain that has gathered inside a building component.

Weld: To join multiple metal or PVC components together by heat fusion.

Wet Bulb Temperature: Air temperature in ° F as measured by a thermometer with a bulb covered by a damp wick.

Wet Film Thickness: The thickness of an uncured material such as a coating.

Wick: To convey liquid by capillary action.

Wind Clip: A clip that slips over the ends of tile, slate and other steep slope roofing materials in order to help prevent wind uplift damage.

Wind Load: The force that wind puts on structures.

Wind Uplift: (1) The upward displacement of a section of a roof system or component caused by movement of air from a location of higher air pressure, such as inside a building, to an area of lower air pressure, such as the surface of a roof during a windy day. Strong wind across the surface of a roof, especially at corners and along perimeters, creates low air pressure above the surface of the roof. Nature will automatically try to compensate for this by moving air from an area of higher pressure such as inside a building. If all penetrations and perimeters are not properly sealed, then "blow-off" can occur. (2) Displacement or blow-off of shingles or other roofing caused by the wind.

Windward: Facing into the wind.

Wire Tie: A system for attaching heavy steep slope roofing materials such as slate r tile by using wire fasteners in addition to or in place of nails.

Woven Valley: A valley construction whereby the valley has a woven look which is effected by overlapping alternate courses of shingles from both sides of the valley.


Z Bar or Z Section: A piece of steel formed in the shape of a "Z."

Zinc: A bluish-white, lustrous metallic element that is brittle at room temperature but malleable with heating. It is used to form a wide variety of alloys including brass, bronze, various solders, and nickel silver, in galvanizing iron and other metals, for electric fuses, anodes, and meter cases, and in roofing, gutters, flashings, edge metals and also for various household objects. Atomic number 30; atomic weight 65.37; melting point 419.4 °C; boiling point 907 °C; specific gravity 7.133 (25 °C); valence 2.



ABC Supply

ABC Supply Co., Inc. is the largest wholesale distributor of roofing in the United States and one of the nation's largest distributors of siding, windows and other select exterior building products, tools and related supplies. Since our start in 1982, we've grown to become a national organization with more than 350 locations in 45 states and the District of Columbia.

Allied Building Products

Allied Building Products Corporation was established in Jersey City, N.J. in 1950as a family-operated roofing and custom sheet metal fabrication business. This firm initially serviced the New York / New Jersey metropolitan area with just five employees, two small trucks, 700 square feet of office, 5000 square feet of warehouse space and a burning desire to build for the future.

Bradco Supply

Ranked as one of the nation's largest distributors of building materials, Bradco Supply is committed to providing contractors and builders with quality products, competitive prices and the best customer service in the industry.

Fraser Cedar Products

At Fraser Cedar Products, we make sure that the exceptional natural qualities of Western Red Cedar are maintained and passed on to you through our stringent quality control program.In-house inspectors, as well as an independent grading agency monitor every step of our production process, to guarantee consistent delivery of only premium shakes and shingles. Each bundle has a bar code.



Founded in 1886, GAF Materials Corporation has grown to become North America's largest manufacturer of residential roofing (sold under the GAF-Elk brand) and commercial roofing (sold under the GAF brand).*Professional installers have long preferred the rugged, dependable performance that only a GAF roof can offer, and have made it the #1-selling brand in North America.*

Owens Corning

Since Owens Corning was founded in 1938, the company has continued to grow as a market-leading innovator of glass fiber technology. A Fortune 500 company for more than 56 years, Owens Corning people redefine what is possible each day to deliver high-quality products and services to customers around the world.


It started with Mastic, a brand with a long history of quality and innovation. Mastic's experience with home exterior solutions began in 1932 when they pioneered the low-maintenance siding market with the introduction of InselBric®, an asphalt-based product that was both durable and attractive. Mastic's innovation continued, with the breakthrough invention of vinyl siding in 1959.


CertainTeed Corporation is a leading North American manufacturer of building materials including roofing, vinyl and fiber cement siding, trim, fence, railing, decking, foundations, insulation, gypsum, ceilings, and pipe products. Headquartered in Valley Forge, Pennsylvania, CertainTeed has approximately 7,000 employees and 70 facilities throughout the United States and Canada. Through its Vision, Mission, Values and Objectives (VMVO) initiative, CertainTeed strives to be the preferred choice for innovative building products and systems by delivering a superior Customer experience to a broader market through the development of exceptional team performance and world-class processes.


TAMKO Building Products, Inc. is a leading manufacturer of residential and commercial roofing products, waterproofing products, composite decking and railing systems, and cements and coatings. Our more than 65 years of success is the direct result of teamwork, enduring relationships with customers, suppliers and employees, and our commitment to Six Sigma continuous quality improvement with its foundation based on the total quality management principles of Dr. W. Edwards Deming.


In 1945 a builder shared a common problem with Clark Belden of installing fixed pitched louvers in homes. It was difficult to cut the right size opening to fit these fixed louvers. Clark solved the problem and Lomanco was officially born on May 4th, 1946, the date the patent for an adjustable louver was filed.


Norandex has nearly 150 distribution branches nationwide, each offering the highest quality residential and light commercial products to professional builders and contractors. Our customers know they can rely on us for a fully stocked inventory and on-time delivery so they can provide homeowners with the highest level of service.

Royal Building Products

For over three decades, our commitment to product innovation, quality and customer relationships has served to attract a growing number of homeowners, architects, engineers and distributors to our products.With operations located throughout North America, Royal Group offers the renovation, remodeling and new construction industries a broad range of innovative products.


Don't settle for cookie-cutter design. Now, you have access to a palette of distinctive choices. Exterior Portfolio™ by Crane is a complete collection of cladding products that will give the face of your home an image you will love. The unlimited design options of Exterior Portfolio have been used to create some of America's most beautiful homes. Now you can enjoy this same impact with the added value of long-lasting, maintenance-free performance.

Rollex Corporation

In the early 1950s, Rollex, a small company with a core expertise in roll forming and extruding metals, was formed. With just 13 people, this promising young business quickly became a fixture in the manufacturing of aluminum and metal moldings for the kitchen, bath, and home exteriors.

Gutter Terms Glossary

Apron Flashing: A horizontal flashing installed where the top end of a roof slope meets a vertical projection, such as a chimney or parapet wall.

Barge: A finishing at the gable end of a roof, fixed parallel to the roof slope.

BMT: Base metal thickness.

Box Gutter: A gutter not at an eave, typically at the base of two opposing roof slopes.

Bid: A formal offer by a contractor, in accordance with specifications for a project, to do all or a phase of the work at a certain price in accordance with the terms and conditions stated in the offer.

Brick mold: Trim used around an exterior doorjamb that siding butts to.

Built-up roof: A roofing composed of three to five layers of asphalt felt laminated with coal tar, pitch, or asphalt. The top is finished with crushed slag or gravel. Generally used on flat or low-pitched roofs.

Cap flashing: The portion of the flashing attached to a vertical surface to prevent water from migrating behind the base flashing.

Capping: A cover at the top of a gap that weatherproofs, typically at the ridge of a pitched roof.

Chimney Gutter: See Soaker.

CGI: See Corrugated Roofing.

Cladding: Sheeting that encloses a building-roofing and walling.

Counter (or over) Flashing: A flashing dressed down as a cover only, over a separate upstand.

Downpipe: A pipe to carry roof water from gutters and roof catchments to drains or storage tanks.

Drainage: A system of gutters and drainpipes that carry water away from the foundation of a house.

Drop: See Pop.

Drop Outlet: Formed piece that serves as the hole from which the water travels from the horizontal section of the gutter to the downspout.

Eaves Gutter: A roof gutter attached at an eaves overhang.

Elbow: Pre-finished angled piece for directing water flow.

Electrolytic (galvanic) Corrosion: Corrosion resulting from the contact of two different metals when an electrolyte (like water) is present.

End Cap: Flat formed piece that is placed at the end of a gutter section.

Expansion Joint: A joint in a long run of cladding, gutter or flashing designed to allow for thermal expansion and contraction.

Fall (slope): The slope of the roof or gutter, often expressed in degrees, or as a ratio of vertical height to horizontal distance (e.g. 1 in 20).

Fascia (fascia board): A flat board that runs horizontally along the eaves of a roof, typically capping the ends of the roof rafters to give the roof edge a more finished look and provide a base for attaching gutters.

Fixings Screws: nails or clouts used to fasten cladding to a building structure.

Flashing: A material, usually metal, used to waterproof the junction between two intersecting roofs and/or wall surfaces. At a masonry wall, it is often built into the mortar.

Galvanized Steel: Steel sheeting protected against corrosion by a zinc coating applied by the continuous hot-dip process.

Girth: The width of the blank strip from which a profile is rolled (usually refers to gutters and flashings).

Gutter: Horizontal channels installed at the edge of a roof to carry rainwater or melted snow away from the house.

Hanger: Flat strap that is installed under the roofing matierial that holds up the horizontal section of the gutter.

Hanging Flashing: Side, front, or back cover piece used to prevent entry of water between abutting surfaces and other gutters, flashings and soakers.

Inside mitre box: A corner piece of the horizontal section that is deflected in.

Leader: A pipe that carries rainwater from the gutters to the ground, sewers, or wells.

Mansard: A roof built at two pitches, the steeper pitch commencing at the eaves and the flatter pitch finishing at the ridge.

Nozzle: See Pop.

Offset: A pipe fitting that directs a downpipe from the gutter, under the eaves soffit and down a wall.

Oilcanning: Variation from flatness of sheet metal, creating undulations along the surface. The result is poor appearance and potential ponding.

Outside mitre box: A corner piece of the horizontal section that is deflected out.

Pan: The flat portion between the ribs in a pan-type preformed sheet.

Parapet: A wall on the perimeter of a building that projects above the line of the eaves.

Penetration: A projection through the roof, e.g. vent pipe, chimney or rooflight.

Pierce-fastened: A method of fixing cladding by means of a screw or nail which pierces the cladding.

Pitch: The angle at which a horizontal section of gutter is tilted in order to force water to flow toward a downspout.

Ponding: Pooling of undrained water on a roof.

Pop: A short fitting in a gutter sole, where rainwater leaves the gutter.

Rainhead: A box-shaped receptacle sometimes used between gutters and downpipes to provide an external overflow point.

R-value: A value given for the resistance to heat transfer of a roof or wall system.

Rib: A longitudinal upstand in cladding.

Ridge Capping: Formed metal designed to weatherproof the junction at the apex of opposing roof slopes.

Run: Length of a horizontal section of gutter.

Saddle Strap: See Straps.

Sarking: A membrane to collect and discharge clear of the structure any water that may penetrate a roof or wall cladding.

Shoe: A fitting used in a downpipe, to change direction of the downpipe by about 45 degrees.

Soaker (gutter): A small gutter located on the upper side of a chimneystack.

Soaker (flashings): A side cover piece extended over a roof cover and overflashed with a hanging flashing. Formed metal designed to weatherproof the perimeter of roof protrusions or penetrations. Soaker flashings are usually positioned under rather than over the surrounding metal roof.

Sole: The internal, bottom surface of a roof gutter.

Splashblock: Plastic or concrete surface put under a downspout to direct water away from the house.

Spreader: A downpipe-tee or elbow fixed at 90 degrees to the roof slope used to spread stormwater over a greater area of the roof.

Spouting: See Gutter.

Strap: Flat hangers that are nailed into the house to hold the downspouts in place.

Sump: A roof gutter pit used to connect downpipes to internal roof gutters.

Thermal Stress: Stress due to expansion and contraction caused by changes in temperature.

Trays: See Pan.

Valley Gutter: A gutter at the bottom intersection of two sloping roofs (also called a valley flashing).

Valley Boards: Timber or profiled metal laid under a valley gutter to support it.

Zincalume: Steel sheeting protected against corrosion by an aluminium-zinc coating

Flood & Water Damage Terms Glossary

Flood Warning Terms

Flash Flood Watch: Indicates that flash flooding is a possibility in or close to the watch area. Those in the affected area are urged to be ready to take action if a flash flood warning is issued or flooding is observed. These watches are issued for flooding that is expected to occur within 6 hours after the heavy rains have ended.

Flash Flood Warning: A flood warning issued for life/property threatening flooding that will occur within 6 hours. It could be issued for rural or urban areas as well as for areas along the major rivers. Very heavy rain in a short period of time can lead to flash flooding, depending on local terrain, ground cover, degree of urbanization, amount of man-made changes to the natural river banks, and initial ground or river conditions. Dam breaks or ice jams can also create flash flooding.

Flash Flood Statement: A Flash Flood Statement is issued to inform the public about current flash flood conditions. These statements usually contain river stage information if major streams or rivers are involved.

Flood Hazard: The potential risk to life and limb and potential damage to property resulting from flooding. The degree of flood hazard varies with circumstances across the full range of floods.

Flood Potential Outlook: A late winter product used to provide information about expected hydrological conditions during the spring thaw.

River Statement: Used to provide information about significant with-in river rises or for river stages nearing the listed flood stage. Also used to provide information about minor ice jams. They frequently contain river stage forecasts.

River Summary: Contains routine hydrological information. Also used to provide a summary of ongoing flooding events.

Urban/Small Stream Flood Advisory: Alerts the public to flooding which is generally only an inconvenience (not life-threatening) to those living in the affected area. Issued when heavy rain will cause flooding of streets and low-lying places in urban areas. Also used if small rural or urban streams are expected to reach or exceed bankfull. Some damage to homes or roads could occur.

Floodplain Definitions

100-Year Flood: Defined by many agencies as the flood having a 1% or greater annual probability of occurring.

500-Year Flood: The flood having a 0.2% or greater annual probability of occurring.

Base Flood: Defined by FEMA as the flood having a 1-percent probability of being equaled or exceeded in any given year; also referred to as the 100-year flood.

Base Flood Elevation (BFE): Defined by FEMA as the height of the base (100-year) flood in relation to a specified datum, usually the National Geodetic Vertical Datum of 1929 or North American Vertical Datum of 1988. Generally speaking, this is the elevation of the 100-year floodwaters relative to "mean sea level". BFE is not depth of flooding. To determine depth of flooding, you would need to subtract the lowest elevation of a particular property from the BFE. For example, if the property's foundation was at an elevation of 125 feet and the BFE was 131 feet, then one might infer that the 100-year depth of flooding would be approximately 6 feet.

Design Flood: A hypothetical flood representing a specific likelihood of occurrence (for example the 100 year or 1% probability flood). The design flood may comprise two or more single source dominated floods. Typical works are filling of land, and the construction of roads, floodways and buildings.

Flood Prone Land: Land susceptible to inundation by the probable maximum flood (PMF) event. The flood prone definition should not be seen as necessarily precluding development. Floodplain Management Plans should encompass all flood prone land (i.e. the entire floodplain) flood-proofing, measures taken to improve or modify the design, construction and alteration of buildings to minimize or eliminate flood damages and threats to life and limb.

Weather Damage Technical Definitions

Average Annual Damage (AAD): Depending on its size (or severity), each flood will cause a different amount of flood damage. The average annual damage is the average damage in dollars per year that would occur in a designated area from flooding over a very long period of time. In many years there may be no flood damage, in some years there will be minor damage (caused by small, relatively frequent floods) and, in a few years, there will be major flood damage (caused by large, rare flood events). Estimation of the average annual damage provides a basis for comparing the effectiveness of different floodplain management measures (i.e. the reduction in the annual average damage).

Average Recurrence Interval (ARI): The long-term average number of years between the occurrence of a flood as big as (or larger than) the selected event. For example, floods with a discharge as great as (or greater than) the 20yr ARI design flood will occur on average once every 20 years. ARI is another way of expressing the likelihood of occurrence of a flood event.

Cubic Feet Per Second (ft3/s, cfs): The rate of discharge representing a volume of 1 cubic foot passing a given point during 1 second and equivalent to 7.48 gallons per second or 448.8 gallons per minute.

Discharge: The volume of water that passes a given point within a given period of time.

Drainage Area: The area, measured in a horizontal plane, enclosed by a topographic divide from which direct surface runoff from precipitation normally drains by gravity into the stream upstream from the specified point.

Drainage Basin: The part of the surface of the Earth that is occupied by a drainage system with a common outlet for its surface runoff, consisting of a surface stream or a body of impounded water with all tributary surface streams and bodies of impounded water. Feeder bands - In tropical systems, feeder bands are the spiral bands of showers and thunderstorms that follow the outer bands and precede the center of the storm. They are often the location of severe weather and can produce copious rains. Circulation around tropical systems can bring the feeder bands over the same areas repeatedly, contributing to high rainfall totals.

Flood Storages: Flood plain areas that are important for the temporary storage of floodwaters during a flood.

Floodway: A flow path (sometimes artificial) that carries significant volumes of floodwaters during a flood.

Gage Height: The water-surface elevation referred to some arbitrary datum. The gage height added to the elevation of the datum of the gage represents the water-surface elevation. For example, the elevation of the datum of the gage might be 100.00 feet, which, when added to a gage height of 12.50 feet, represents a water-surface elevation of 112.50 feet.

Isohyetal: Line of equal precipitation.

Low-Level Jet: A relatively fast-moving (20 to 60 miles per hour) layer of air that forms 1,000 to 3,000 feet above the surface. The low-level jet is a summertime nocturnal event, forming above the nighttime inversion as the air near the surface cools bringing low-level stratus clouds (late night and morning low clouds) to south-central Texas. It is also associated with flow off the Gulf of Mexico during spring through fall, bringing moisture rapidly back into Texas and the Plains as high pressure systems move eastward behind departing cold fronts. This low-level jet provides much of the moisture needed for thunderstorm development in this area.

Peak Flood Level, Flow or Velocity: The maximum flood level, flow or velocity occurring during a flood event.

Precipitable Water (PW): The total atmospheric water vapor contained in a vertical column extending between any two specified levels, generally from the ground to the top of the upper-air sounding, expressed in terms of the height to which the water would stand if completely condensed and collected in a vessel of equal cross section as the column. Two inches is a very moist, tropical atmosphere capable of producing copious amounts of rain. In central Texas 2-inch PWs are routinely seen only in association with inland tropical activity.

Runoff: The part of the precipitation that appears in surface streams.

Runoff in Inches: The depth to which the drainage area would be covered if all the runoff for a given period were uniformly distributed on it.

Stage Hydrograph: A graph of water level over time.

Steering Sinds: The flow exerting influence over the movement of a disturbance, such as a thunderstorm. Steering winds for thunderstorms typically extend from 10,000 to 20,000 feet.

Streamflow: The discharge that occurs in a natural channel.

Tropical Barotropic: Barotropic describes the condition of the atmosphere when lines of constant temperature are parallel to lines of constant pressure through the depth of the atmosphere. True barotropic conditions are rarely achieved but come closest in tropical weather systems. Wind shear, the change of wind speed and (or) direction with height, is weak in barotropic systems making them conducive to the production of heavy rain.

Tropopause: The boundary between the troposphere and the stratosphere. "Weather," as we know it, occurs within the troposphere, that part of the atmosphere closest to the Earth's surface (6.2 to 12.4 miles deep). Temperature decreases with height within the troposphere. The tropopause is marked by an abrupt change of lapse rate (the change of temperature with height).

Upper-Level Diffluence: Diffluence is the rate at which adjacent flow is diverging along an axis normal to the flow at the point in question. Upper-level diffluence (between 15,000 and 30,000 feet), a spreading out of the airflow, places lower-speed winds in the region critical to thunderstorm movement. This slow movement leads to higher rainfall totals as storms remain over a location longer and contributes to storms developing and moving continually over the same areas.

Velocity: The speed at which the floodwaters are moving. Typically, modeled velocities in a river or creek are quoted as the depth and width averaged velocity, i.e. the average velocity across the whole river or creek section.

Watershed: The divide separating one drainage basin from another. However, over the years, the term has evolved to represent the drainage basin.

Water Damage Definitions

Air Mover: Turbo Air Mover, Fans, Dryers. A specialized type of fan that promotes evaporation of moisture by design. Air movers incorporate an electric motor, fan and specially designed shape and housing to promote rapid drying of carpets, pad, sub flooring, walls and framing members. They are also used for drying under cabinets and other hard to reach areas.

Baseboards: Wooden, Multi-Desnsity Fiberboard, Tile, Stone or Plastic board, normally one inch to twelve inches (75-300 mm) high, covering the lowest part of an interior wall. Its purpose is to cover the joint between the wall surface (usually plaster or drywall) and the floor. It covers the inevitable uneven edge as flooring meets the wall. As a secondary function, it protects the wall from kicks and abrasion and sometimes prevents furniture from being pushed right against the wall.

Boroscope: A hand-held tool that allows the user to see potential mold problems inside walls, ceilings, crawl spaces, and other tight spaces. It consists of a camera on the end of a flexible "snake". No major drilling or cutting of dry wall is required.

Category 1 Water: Water originating from a source that does not pose substantial harm to humans. (Also referred to as "Clean Water")

Category 2 Water: Water containing a significant degree of chemical, biological and/or physical contamination and having the potential to cause discomfort or sickness if consumed by or exposed to humans. (Also referred to as "Gray Water")

Category 3 Water: Grossly unsanitary water, containing pathogenic agents arising from sewage or other contaminated water sources and having the likelihood of causing discomfort or sickness if consumed by or exposed to humans. This category includes all forms of seawater, ground surface water, and rising water from rivers or streams. (Also referred to as "Black Water")

The Four IICRC Water Damage Classifications:

Class 1: Slow Evaporation Rate: Water losses that affect only part of a room or area, or losses with lower permeance/porosity materials (e.g., plywood, particle board, structural wood, VCT, concrete). Little or no wet carpet or cushion is present. Minimum moisture is absorbed by materials, releasing moisture slowly.

Class 2: Fast Evaporation Rate: Water damage losses that affect an entire room or carpet and cushion. Water has wicked up walls 12" - 24". There is moisture remaining in structural materials (e.g., plywood, particleboard, structural wood, concrete).

Class 3: Fastest Evaporation Rate: Water may have come from overhead. Ceilings, walls, insulation, carpet, cushion and sub-floor in the entire area are saturated.

Class 4: Specialty Drying Situations: These consist of wet materials with very low permeance/porosity (hardwood, plaster, brick, concrete, stone, crawlspace). Typically, there are deep pockets of saturation, which requires very low specific humidity.

Dehumidifier: A mechanical device that promotes the reduction of moisture in the air. These devices when used properly with air movers, greatly reduce the amount time taken to dry structural building materials, thereby greatly reducing the risk of unwanted microbial growth.

Drywall, Sheetrock, Gypsum Board: is the term used for a common method of constructing interior walls and ceilings using panels made of gypsum plaster pressed between two thick sheets of paper, then kiln dried. Many such panels are made with fiberglass instead of paper to prevent mold growth, which is common with paper that has been exposed to water due to plumbing leaks or floods. Drywall construction is used globally for the finish construction of interior walls and ceilings.

Moisture Meter: A tool that measures the moisture level in building materials. It can also be used to measure the progress of the drying of damaged materials. Moisture meters have a small probe that is inserted into the material, or pressed directly against the material's surface. Moisture meters can be used on carpet, wallboard, woods, brick, and other masonry.

PPE (Personal Protective Equipment): Includes respirators, gloves, impervious suit, and eye protection. These items can be used during the assessment and remediation processes.

Relative Humidity: The ratio of the amount of water vapor in the air at a specific temperature to the maximum amount that the air could hold at that.

Subfloor: A rough floor, usually constructed of plywwood, oriented strand board, 2 x 6 boards or cement over which a finished flooring material, such as: carpet, laminate, engineered wood flooring, hardwood floor or other finished flooring product is installed.

Thermal Hygrometer: Measures the amount of humidity in the indoor environment. Often gauges are paired with a thermometer to measure the temperature.

Underlayment: A material placed under finished floor coverings. Underlayment is usually constructed of smooth particle board providing an even surface for finished flooring such as linoleum, sheet vinyl, and vinyl.

Siding Terms Glossary

Alcoa : Manufacturer of aluminum siding.

Aluminum Siding : Horizontal planks of aluminum with a baked-on enamel finish that looks like lap siding.

American Hardboard Association (AHA) : The national trade organization for the manufacturers of hardboard products

American National Standards Institute (ANSI) : ANSI is a private, nonprofit organization that oversees the voluntary standardization and assessment of US products, to enable the US to better compete globally and enhance the quality of life in the US by conformity to product standards

Backerboard : A flat material used on the face of the house, between the studs and the siding, to provide a nailable surface for the siding.

Battens : Narrow strips of wood placed over joints in vertical wood plank siding to seal the joints

Beveled Clapboards : that are tapered rather than cut perfectly rectangular

Board and Batten : A style in which a narrow strip of siding appears to cover the seam between two wider boards. Board and batten siding is installed vertically.

Brick veneer : A wall construction method in which a layer of bricks is attached to the wood framework of a house using brick ties

Buttlock : Located on the bottom edge of a vinyl panel which locks onto the previously installed panel

Caulking : Waterproof material used to seal joints.

Certainteed : Manufacturer of fiber cement and vinyl siding.

Channel : The area of the accessory trim or corner post where siding or soffit panels are inserted. Channels also refer to the trim itself, and are named for the letters of the alphabet they resemble, for example J-channel and F-channel are available.

Checking : A crack or split along the grain in wood plank siding as a result of cupping

Clapboard : Overlapping, horizontal wood plank siding made from either rectangular planks or taped planks

Composition board : Blanks or sheets of weather resistant compressed wood fibers used as siding

Corrugated Siding : Siding made out of aluminum or plastic derivatives having ridges and valleys and is attached to the sides of buildings.

Course : A row of panels, one panel wide, running the length of the house from one side to the other or, in the case of vertical siding, from top to bottom.

Cupping : A warp across the board in wood plank siding

D4 Profile : Two four-inch wide horizontal traditional planks per single panel of siding.

D5 Profile : Two five-inch wide horizontal traditional planks per single panel of siding.

Detachment Separation : of the siding material-veneer or stucco- from its attachment to the house

Double course : An undercourse of shingles or shakes, not exposed to the weather, is covered completely by a top course

Double Wall Siding : Siding in which sheathing is installed and is then covered by exterior siding.

Drip Cap/Head Flashing : An accessory installed with vertical siding to ensure that water drips away from panels and does not infiltrate them; it is also used as a vertical base.

Dutchlap or Shiplap : A more decorative variation on the clapboard style where the face (or width) of the board is beveled for added dimension.

F-channel : A manufacturing component of vinyl or aluminum siding systems which have a channel that the planks fit into, used around windows and doors to make a weathertight seal

Face : The part of the vinyl panel that is visible once the vinyl is installed

Fascia Board : A board attached to the ends of the rafters between the roofing material and the soffit overhang. Fascia cap is the covering around that board.

Flashing : A type of sheet metal used at intersections of building components to prevent water penetration, flashings are commonly used above doors and windows in exterior walls and are used under the siding to prohibit water penetration

Fiberboard Siding: This type of siding is made of composite wood material, and is sold under several brand names, including Masonite. Because it is not made of solid wood, it must be installed and maintained properly.

Furring/Furring Strip: A wooden or steel framing material, usually 1" x 3", used to provide an even nailing base. To "fur" a surface means to apply these strips.

Gentek : Manufacturer of aluminum, seamless steel and vinyl siding.

Georgia Pacific : Manufacturer of wood siding.

J-channel: A manufacturing component of vinyl or aluminum siding systems which have a curved channel that the planks fit into, used around windows and doors to make a weathertight seal.

James Hardie : Manufacturer of fiber cement siding.

Lap : The part of the roofing/siding material that overlaps a section of adjacent material.

Lap Siding: Technique for installing horizontal siding boards. Each piece of siding is 'lapped' over the piece below it to provide a waterproof covering for the house.

Milled planks : Various cuts of plank siding, including V-groove, channel, rabbeted bevel, shiplap and drop

Moisture permeable : A surface that allows moisture to pass through it

Nailing Hem (or Flange) : The section of siding or accessories where the nailing slots are located.

Napco : Manufacturer of aluminum and vinyl siding.

Owens Corning : Manufacturer of aluminum and vinyl siding.

Panel Projection: The amount that a panel of vinyl sticks out away from the wall, you should choose the largest profile for the style of panel you want

Panel Siding: comes in sheets, normally 4 feet by 8 feet. Examples of panel siding include Texture 1-11. Because panel siding can be installed quickly, it can be a less expensive option than other types of siding.

Plywood siding : Plywood sheets, some with a grooved or decorative outer surface Positive Lock:

Positive Lock : ensures that the panels can be locked together, but can also easily slide back and forth for ease in installation. This ensures that the panels stay permanently affixed during adverse weather.

Plumb : A position or measurement that is truly and exactly vertical, 90° from a level surface.

Profiles : The actual siding panels are called profiles. Some commonly sized profiles are D4, D5 and Dutchlap.

Scarfed joint: Joint used in plywood siding where edges of abutting sheets are angle cut to fit snugly and prevent water penetration

Shake Siding: Sometimes known as shingle siding, shake siding comes in widths from about four inches to 12 inches. It is installed like lap siding, starting at the lowest row, and moving up the wall. The random widths of the shakes provide a distinctive look to the wall.

Single Coursing: Single layer of siding shingles applied with a small overlap along the edge of the course below.

Single Wall Siding : Exterior wall siding that is not applied over sheathing.

Soffit : Material used to enclose the horizontal underside of an eave, cornice, or overhang. Some soffit panels may also be used as vertical siding.

Spalling : Crumbling and falling away of bricks, concrete or blocks

Square : Unit of measure for siding equal to 100 square feet (or a 10-foot by 10-foot wall section).

Square Feet : (also known as: Exterior Square Feet) Exterior Square Feet is a term used to denote the total amount of siding material needed for a particular siding job including material waste.

Stucco : A type of water resistant, plaster like siding material made of cement, sand and water; it may have an acrylic finish

Tounge and Groove (T&G): Tongue and groove, a connection system between components, like wood, in which the tab or tongue of one board is placed into the grove at the end of another board

T 1-11 : Hardboard, exterior siding that has vertical grooves made to simulate separate boards.

T3 Profile : Three three-inch wide horizontal traditional planks per single panel of siding.

United States Seamless : Manufacturer of seamless steel siding.

Variform : Manufacturer of vinyl siding.

Vinyl Siding : Horizontal polyvinyl chloride planks

Veneer: Veneer is one ply or one thickness of something; in siding there are brick and stone veneers, there are also veneers of one wood bonded to another

Wall Cladding : Another term for siding

Wall Sheathing : Sheets of plywood or wood planking used to cover the wall framework of the house

Weep Hole : A small hole in the bottom butt edge of the vinyl siding panel, allowing condensation to escape. .

Windload Pressure: Is a measurement of how well a panel might perform in high wind areas

Wire Mesh : A mesh attached to the wall sheathing and studs used to anchor a stucco base coat to the wall

Wood Plank Siding : Rectangular wood planks, installed horizontally or vertically

Wood Shakes : Thick, rough, uneven shingles that hand split, split and sawn on one side, or sawn on both sides, used as siding

Wood Shingles : Sawn shingles that are of uniform thickness

Commercial Glossary

Aggregate : (1) crushed stone, crushed slag or water-worn gravel used for surfacing a built-up roof. (2) any granular mineral material. 

Alligatoring : the cracking of the surfacing bitumen on a built-up roof, producing a pattern of cracks similar to an alligator's hide; the cracks may or may not extend through the surfacing bitumen.

Ambient Temperature : temperature of air - - air temperature. 

Application Rate : the quantity (mass, volume or thickness) of material applied per unit area. 

Area Divider : a raised, double wood member attached to a properly flashed wood base plate that is anchored to the roof deck. It is used to relieve thermal stresses in a roof system where no expansion joints have been provided.

Asbestos : (a group of natural, fibrous, impure silicate materials.

Asphalt : A dark brown to black material in which the predominating constituents are bitumen's, which occur in nature or are obtained in petroleum processing. 

Asphalt, Air Blown : an asphalt produced by blowing steam through molten asphalt to modify its properties, normally used for highway bitumen. 

Atactic Polypropylene : a group of high molecular weight polymers formed by the polymerization of propylene.

Back Nailing : the practice of blind nailing (in addition to hot mopping) all the plies of a substrate to prevent slippage. see Blind Nailing

Ballast : an anchoring material, such as aggregate, precast pavers, which employ the force of gravity to hold (or assist in holding) membranes in place. 

Base Flashing : see Flashing


Ply : the base ply is the first ply when it is a separate ply and not part of a shingled system.

Base Sheet : a saturated or coated felt placed as the first ply in some multi-ply built up roof membranes. 

Bentonite : a clay formed from decomposed volcanic ash, with a high content of the mineral montmorillonite; has the capacity of absorbing a considerable amount of water, and swells accordingly. 

Bitumen : the generic term for an amorphous, semi-solid mixture of complex hydrocarbons derived from any organic source. Asphalt and coal tar are the two used in the roofing industry.

Bituminous : containing or treated with bitumen. Examples- bituminous concrete, bituminous concretes, bituminous felts and fabrics, bituminous pavement. 

Bituminous Grout : a mixture of bituminous material and fine sand that will flow into place without mechanical manipulation when heated. 

Blind Nailing : the practice of nailing the back portion of a roofing ply. 

Blister : a spongy raised portion of a roof membrane, ranging in area from 1 inch in diameter and of barely detectable height upward. Blisters result from the pressure buildup of gases entrapped in the membrane system. these gases most commonly are air and/or water vapor. Blisters usually involve de-lamination of the underlying membrane plies. 

Bond : the adhesive and cohesive forces holding two roofing components in intimate contact. 

Brooming : embedding a ply of roofing material by using a broom to smooth out the ply and ensure contact with the adhesive under the ply. 

BTU : (British Thermal Unit) - the heat energy required to raise the temperature of 1 pound of water 1 degree Fahrenheit. 

Buckle : an upward, elongated tenting displacement of a roof membrane frequently occurring over insulation or deck joints. A buckle may be an indication of movement within a roof assembly, and usually associated with improper installation. 

Built-up Roof Membrane : a continuous, semi-flexible roof membrane assembly, consisting of plies of saturated felts, coated felts, fabrics or mats between which alternate layers of bitumen are applied, generally surfaced with mineral aggregate, bituminous materials, or a granule-surfaced roofing sheet. (Abbreviation: BUR.) 

Butyl : a rubber like material produced by copolymerizing isobutylene with a small amount of isoprene, Butyl may be manufactured in sheets, or blended with other elastomeric materials to make sealants and adhesives. 

Cant Strip : a beveled strip of wood or wood fiber that fits into the angle formed by the intersection of a horizontal surface and a vertical surface. The 45-degree slope of the exposed surface of the cant strip provides a gradual angular transition from the horizontal surface to the vertical surface. see Flashing 

Capillary : the action by which the surface of a liquid (where it is in contact with a solid) is elevated or depressed, depending upon the relative attraction of the molecules of the liquid for each other and for those of the solid. 

Cap Sheet : a granule-surfaced coated sheet used as the top ply of a built-up roof membrane or flashing. 

Caulking : a composition of vehicle and pigment, used at ambient temperatures for filling joints, that remains plastic for an extended time after application. 

PolyChlorinated ethylene(CPE) : a thermoplastic material, used for single ply roof membranes, composed of high molecular weight polyethylene which has been chlorinated. 

Chlorosulfonated Polyethylene(CSPE or CSM)(Hypalon) : a synthetic, rubber like thermoset material, based upon high molecular weight polyethylene with suphonyl chloride, usually formulated to produce a self vulcanizing membrane. 

Coal Tar Bitumen : a dark brown to black, semi-solid hydrocarbon formed as a residue from the partial evaporation or distillation of coal tar. It is used as the waterproofing agent in dead-level or low-slop built-up roofs. It differs from COAL TAR PITCH in having a lower front-end volatility. 

Coal Tar Felt : see Tarred Felt 

Coal Tar Pitch : A dark brown to black, semi-solid hydrocarbon formed as a residue from the partial evaporation or distillation of coal tar. It is used as the waterproofing agent in dead-level or low-slope built-up roofs. (For specification properties, see ASTM Standard D 450, Types 1 and II.) 

Coated Base Sheet : a felt that has been impregnated and saturated with (or felt) asphalt and then coated on both sides with harder, more viscous asphalt to increase its impermeability to moisture; a parting agent is incorporated to prevent the material from sticking to the roll. 

Cold Process : a continuous, semi-flexible roof membrane, consisting of plies of felts, mats or fabrics that are laminated on a roof with alternate layers of cold-applied roof cement and surfaced with a cold-applied coating. 

Condensation : the conversion of water vapor or other gas to liquid as the temperature drops or the atmospheric pressure rises. see Dew-Point

Coping : the covering piece placed on top of a wall that is exposed to the weather. It is usually sloped to shed water.

Counter flashing : formed metal or elastomeric sheeting secured on or into a wall, curb, pipe, rooftop unit or other surface to cover and protect the upper edge of a base flashing and its associated fasteners.