Roofing Glossary Terms

Affordable Roofing by John Cadwell, Inc. Roofing Glossary.

We recommend roofing customers be familiar with these common roofing definitions. It will help customers understand the terms when reviewing the estimate, warranty, and/or any other roof related documents.

If you have any questions about these terms please feel free to Contact Us.

Roofing Glossary and Terms
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  • 1

  • 15lb
    A prepared felt roll roofing with a granule surfacing that has a mass of approximately 15 pounds per 100 square feet.
  • 15lb.,15 lb., 15-pound
    A prepared felt roll roofing with a granule surfacing that has a mass of approximately 15 pounds per 100 square feet.
  • 3

  • 3-Tab Shingle
  • 30lb
    A prepared felt roll roofing with a granule surfacing that has a mass of approximately 30 pounds per 100 square feet.
  • 30lb.,30 lb., 30-pound
    A prepared felt roll roofing with a granule surfacing that has a mass of approximately 30 pounds per 100 square feet.
  • 4

  • 45lb
    A prepared organic felt roll roofing with a granule surfacing that has a mass of approximately 45 pounds per 100 square feet.
  • 45lb.,45 lb., 45-pound
    A prepared organic felt roll roofing with a granule surfacing that has a mass of approximately 45 pounds per 100 square feet.
  • 9

  • 90lb
    A prepared felt roll roofing with a granule surfacing that has a mass of approximately 90 pounds per 100 square feet.
  • 90lb.,90 lb., 90-pound
    A prepared felt roll roofing with a granule surfacing that has a mass of approximately 90 pounds per 100 square feet.
  • a

  • Abrasion Resistant
    The term used to describe the ability to resist being worn away by contact with another moving, abrasive surface, such as foot traffic, mechanical equipment, wind-blown particles, tree limbs, etc.
  • Acclimate
    A process of becoming accustome to a new climate or to new conditions.
  • Acrylic Coating
    A coating system based on an acrylic resin. Generally, a latex-based coating system which cures by air drying.
  • Acrylic Resin
    Polymers of acrylic or methacrylic monomers. Often used as a latex base for coating systems.
  • Adhere
    Two surfaces to be held together by adhesion, typically with asphalt or roofing cements in built-up roofing and with contact cements in some single-ply membranes.
  • Adhesive
    Materials made up to adhere to two or more surfaces.
  • Aggregate
    Rock, stone, crushed stone, crushed slag, water-worn gravel or marble chips used for surfacing and/or ballasting a roof surface.
  • Aging
  • AL
    A non-rusting metal sometimes used for metal roofing and flashing.
  • Algae
    A rooftop growth of organic nonflowering plant that can cause a dark streaking discoloration of roofing materials that can also cause damage to your roof and reduce the roofs lifespan, prematurely causing you to replace your roof early.
  • Alligatoring
    The term for cracking of the surfacing bitumen on a built-up roof, producing a pattern of cracks like an alligator’s hide; the cracks may or may not extend through the surfacing bitumen.
  • Alloy
    A metal made by combining two or more metallic elements, especially to give greater strength or resistance to corrosion.
  • Aluminized Steel
    Sheet steel with a thin aluminum coating bonded to the surface to enhance weathering characteristics.
  • Aluminum
    A non-rusting metal sometimes used for metal roofing and flashing.
  • American Society for Testing and Materials
    A voluntary organization concerned with development of consensus standards, testing procedures and specifications.
  • Anti-Ponding Taper Strips
    A preformed molded product commonly used with raised fascia to help prevent water from collecting behind raised fascia and causing rot.
  • Application Rate
    The quantity (mass, volume, or thickness) of material applied per unit area.
  • Apron Flashing
    A term used for a flashing located at the juncture of the top of the sloped roof and a vertical wall or steeper-sloped roof.
  • Architectural Metal Panel
    A metal roof panel, typically a double standing seam, flat panel, or batten seam; on a slope to shed water.
  • Architectural Shingles
  • Area Divider
    A raised, flashed assembly (typically a single- or double-wood member attached to a wood base plate) 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 (sometimes between expansion(...)
  • Asbestos
    An incombustible fibrous mineral form of magnesium silicate formerly used for fireproofing and sometimes used for the reinforcement of roofing materials. A well-recognized as a health hazard and its use is now highly regulated by both OSHA and EPA.
  • Asphalt
    A dark brown or black substance found in a natural state or more commonly, left as a residue after evaporating or otherwise processing crude oil or petroleum. It is bituminous waterproofing agent applied to some roofing materials during manufacturing.
  • Asphalt, Air Blown
    Produced by blowing air through molten asphalt held at an elevated temperature, to raise the asphalt’s softening point and modify other properties.
  • Asphalt Emulsion
    A mixture of asphalt particles and an emulsifying agent such as bentonite clay and water. These components are combined by using a chemical or a clay emulsifying agent and mixing or blending machinery.
  • Asphalt Felt
    An asphalt-saturated and/or an asphalt-coated felt.
  • Asphalt Primer
    See Primer.
  • Asphalt Roof Cement
    A spreadable mixture of solvent-based bitumen, mineral stabilizers, other fibers and/or fillers. Also known as Flashing Cement or Roofing Cement.
  • Asphaltene
    A high molecular weight hydrocarbon fraction precipitated from asphalt by a designated solvent (paraffinic naphtha) at a specified temperature and solvent-asphalt ratio.
  • ASTM
    A voluntary organization concerned with development of consensus standards, testing procedures and specifications.
  • Atactic Polypropylene
    A group of high molecular weight polymers formed by the polymerization of propylene.
  • Attic
    The open space above the ceiling and immediately under the roof deck of a steep-sloped roof.
  • b

  • Back-Nailing
    The method of fastening the back or upper side of a ply of roofing felt or other component in a roof system so that the fasteners are covered by the following ply.
  • Back-Surfacing
    Fine mineral matter applied to the back side of asphalt shingles and roll roofing during manufacturing.
  • Ballast
    An anchoring material, such as aggregate, or precast concrete pavers, which employs the force of gravity to assist or hold single-ply roof membranes in place.
  • Barrel Vault
    A building profile featuring a rounded profile to the roof on the short axis, but with no angle change on a cut along the long axis.
  • Base Flashing
    Plies or strips of roof membrane material used to close off and/or seal a roof at the roof-to-vertical intersections, such as at a roof-to-wall juncture. Membrane base flashing covers the edge of the field membrane.
  • Base Ply
    The lowermost ply of roofing in a roof membrane or roof system.
  • Base Sheet
    A saturated or coated felt placed as the first ply in some multi-ply built-up and modified bitumen roof membranes.
  • Batten
    In a metal roof: a metal closure set over, or covering the joint between, adjacent metal panels; or wood: a strip of wood commonly set in or over the structural deck; or in a membrane roof system: a narrow plastic, wood, or metal bar which is used to fasten or hold the roof membrane and/or(...)
  • Bermuda Seam
    A metal roof that has a step profile.
  • Bird Screen
    Wire mesh installed over openings in order to prevent birds from entering a building or roof cavity
  • Bird Stop
    See Edge Vent Riser.
  • Bitumen
    A class of amorphous, black or dark colored, (solid, semi-solid, or viscous) cementitious substances, natural or manufactured, composed principally of found in petroleum asphalts, coal tars and pitches, wood tars and asphalts; or a generic term used to denote any material composed principally(...)
  • 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
    A suspension of minute particles of bituminous material in water or other aqueous solution. Also known as Asphalt Emulsion.
  • Blackberries
  • Blanket (Batt) Insulation
    Fiberglass or other compressible fibrous insulation, generally available in roll form.
  • Bleed-Sheet
    A sheet material used to prevent the migration of bitumen.
  • Bleeder Strip
  • Blind-Nailing
    The method of installing fasteners that are not exposed to the weather in the finished roofing system. The practice of nailing the back portion of a roof covering so that the fasteners are covered by other roofing material. Also known as Conceal nail method.
  • Blister
    A term to describe an enclosed pocket of air, which may be mixed with water or solvent vapor, trapped between impermeable layers of felt or membrane and substrate creating the appearance of bubbles.
  • Blocking
    A piece of dimensional lumber and/or plywood secured to the structural deck or walls, which provides a receiving medium for the fasteners used to attach membrane or flashing. Also known as Nailer.
  • Blow-Off
    When roofing materials that were subjected to high winds and are forced off.
  • Bond
    The adhesive and/or cohesive forces holding two components in positive contact.
  • Boot Pipe Flashing
  • Boot Vent Flashing
    Covering made of flexible material, which may be pre-formed to a shape, used to prevent dust, dirt, water, etc., from around a bathroom pipe penetration from roof. Also known as a plumbing boot or pipe flashing.
  • Brake
    A device operated by hand or power used to form metal.
  • Brick Flashing
  • Bridging
    A method of reroofing with metric sized shingles.
  • 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 the roof assembly.
  • Built-Up Roof Membrane
    A flat or low-slope roof consisting of multiple layers of asphalt and ply sheets.
  • Bundle
    A package of shingles. There are 3, 4 or 5 bundles per square depending on the type of shingles.
  • BUR
    A flat or low-slope roof consisting of multiple layers of asphalt and ply sheets.
  • Butt Edge
    The lower edge of the shingle tabs.
  • Butt Joint
    A term for a joint formed by adjacent, separate sections of material, such as where two neighboring pieces of insulation abut.
  • Butterfly Roof
    A type of roof framing style that has inverted roof deck in the shape of a “V”.
  • Button Punch
    A process of indenting two or more thicknesses of metal that are pressed against each other to prevent slippage between the metal.
  • Butyl
    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.
  • Butyl Coating
    An elastomeric coating system derived from polymerized isobutylene.
  • Butyl Rubber
    Synthetic elastomer based on isobutylene and a minor amount of isoprene.
  • Butyl Tape
    A sealant tape sometimes used between metal roof panel seams and end laps; also used to seal other types of sheet metal joints, and in various sealant applications.
  • c

  • C
    A unit of heat flow that is used for specific thicknesses of material or for materials of combination or composite construction, such as laminated insulation.
  • C-Channel
    A structural framing beam, used primarily in building construction and civil engineering. Commonly made of metal.
  • C-Flashing
  • Canopy
    Any overhanging or projecting roof structure, typically over entrances or doors. Sometimes the extreme end is unsupported. Commonly found over entrances or driveways.
  • Cant
    The act of installing Cant Strip at a right angle adjunct.
  • Cant Flashing
  • Cant Strip
    A triangular-shaped strip of material used to ease the transition from a horizontal plane to a vertical plane. Commonly made of wood, wood fiber, perlite, or other materials.
  • Cap Sheet
    Granule-surface coated sheet used as the top ply of some built-up or modified bitumen roof membranes.
  • Capacitance Meter
    Device used to locate moisture or wet materials within a roof system by measuring the ratio of the change to the potential difference between two conducting elements separated by a non-conductor.
  • Capillary Action
    The action that causes movements of liquids by surface tension when in contact with two adjacent surfaces such as panel side laps.
  • Caulk
    A material used for filling/sealing joints or junctures, where no elastomeric properties are required.
  • Caulking
    Sealing and filling the joints, seams, or voids between adjacent units by filling with a sealant or caulk.
  • Cavity Wall
    A wall built or arranged to provide an air space within the wall (with or without insulating material), in which the inner and outer materials are tied together by structural framing.
  • CCF
    100 cubic feet
  • Cementitious Waterproofing
    Heavy cement-based compounds and various additives that are mixed and packaged for use in a dry form; the packaged moisture is then mixed with water and liquid bonding agents to a workable concrete-like consistency.
  • Chalk Box
    A string-cord in container used to make a line made on the roof by snapping the stretched-taut string-cord dusted with chalk. Used for alignment purposes.
  • Channel Flashing
    A type of flashing used at roof-to-wall junctures and other roof-to-vertical plane intersections where an internal gutter is needed to handle run-off. Commonly used with profile tile on steep roofing.
  • Chevron
    Style of metal panel seaming/design.
  • Chimney
    Stone, masonry, prefabricated metal, or a wood framed structure, containing one or more flues, projecting through and above the roof. Commonly used for fireplaces.
  • Chimney Cap
    A rain cover on top of a chimney flue designed to keep out rain and a device to improve the light wind of a chimney, by presenting a protected exit opening and prevent downward drafts into the chimney. It can help prevent invading rodents and can help protect the roof from burning embers.
  • Chlorinated Polyethylene
    Thermoplastic material, used for single-ply roof membranes, composed of high molecular weight polyethylene which has been chlorinated - a process that yields a flexible rubber-like material.
  • Chloro-Sulfonated polyethylene
    Synthetic, rubber-like thermoset material, based on high molecular weight polyethylene with sulphonyl chloride, usually formulated to produce a self-vulcanizing membrane.
  • Cladding
    A material used as the exterior wall enclosure of a building.
  • Class A, B and C Fire Ratings
    Fire-resistance ratings were established for roofing per ASTM and UL tests. These indicate the resistance of a roofing system to fires originating from sources outside the building.
  • Cleat
    A metal strip, plate or metal angle piece, either continuous or individual (“clip”), used to secure two or more components together.
  • Climaseal®
    Tradename of coating. Coating is formulated to react and form a long-life protection for optimum corrosion resistance and it exhibits excellent resistance to most forms of abrasion and torque. A type of Polymer.
  • Clip
    A small metal component used to secure two pieces of metal to each other or to secure metal shingles or standing seam to solid decking.
  • Closed Cut Valley
    A method of valley treatment in which shingles from one side of the valley extend across the valley, while shingles from the other side are trimmed away from the valley centerline. The valley flashing is not exposed.
  • Closure Strip
    A metal or resilient strip, such as neoprene foam, used to close openings created by joining metal panels, or sheets, and flashings.
  • Coal-Tar Felt
    A felt that has been saturated with refined coal tar.
  • Coal-Tar Roof Cement
    A spreadable mixture of processed coal-tar base, solvents, mineral fillers and/or fibers.
  • Coated Base Sheet
    A felt that has previously been saturated with asphalt and later coated with harder, more viscous asphalt, which greatly increases its impermeability to moisture.
  • Coated Felt Sheet
    An asphalt-saturated felt that has also been coated on both sides with harder, more viscouscoatingasphalt; or a glass fiber felt that has been simultaneously filled and coated with asphalt on both sides.
  • Coating
    A layer of material spread over a surface for protection or decoration.
  • Cohesion
    The degree of internal bonding of one substance to itself.
  • Coil Coating
    The application of a finish to a coil of metal using continuous mechanical coating process.
  • Cold Forming
    The process of using press brakes, roll formers, etc., to shape metal into desired profiles at ambient room temperature.
  • Cold Process Built Up Roof
    A continuous, semi-flexible roof membrane, consisting of a ply or plies of felt mats or other reinforcement fabrics that are laminated together with alternate layers of liquid-applied (usually asphalt-solvent based) roof cements or adhesives installed at ambient or a slightly elevated temperature.
  • Cold Rolled
    The process of forming steel into sheets, panels, or shapes on a series of rollers at ambient room temperatures.
  • Collar
    Pre-formed flange placed over a vent pipe to seal the roof around the vent pipe opening. Also known as vent sleeve or Storm Collar.
  • Collector Head
    A component used to direct water from a through-wall scupper to a downspout.
  • Column
    A vertical structural member placed on a footing or foundation used to support horizontal above-ground building components.
  • Combustible
    Capable of burning.
  • Compatible Materials
    Two or more substances that can be mixed, blended, or attached without separating, reacting, or affecting the materials adversely.
  • Compound Thermoplastics
    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.
  • Compressive Strength
    The ability of materials and components to resist deformation or other damage caused by the weight of compression of either live or dead loads.
  • Concealed-Nail Method
    A method of asphalt roll roofing application in which all nails are driven into the underlying course of roofing and covered by an adhered, overlapping course.
  • Condensation
    The change of water from vapor to liquid when warm, moisture-laden air meets a cold surface.
  • Conductor Head
    A transition component between a through-wall scupper and downspout to collect and direct run-off water.
  • Cone Top
  • Construction Joint
    A formed or assembled joint at a predetermined location where two successive placements of concrete meet.
  • Contact Cements
    Adhesives used to adhere or bond various roofing components. These adhesives adhere mated components immediately on contact of surfaces to which the adhesive has been applied.
  • Contamination
    The process of making a material or surface unclean or unsuited for its intended purpose, usually by the addition or attachment of undesirable foreign substances.
  • Coping Cap Flashing
    The covering piece on top of a wall which is exposed to the weather, usually made of metal, masonry, or stone. Used to cover or shield the upper edges of the membrane base flashing; wall flashing can also be used to cover the top of different building components, such as columns or parapet(...)
  • Copolymer
    The product of polymerization of two or more substances at the same time; a “mixed” polymer.
  • Copolymerization
    A chemical reaction that results in the bonding of two or more dissimilar monomers to produce large, long-chain molecules which are copolymers.
  • 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 is a natural weathering metal used in metal roofing that turns a greenish color after being exposed to the weather for a length of time.
  • Cornice
    The decorative horizontal molding or projected roof overhang.
  • Corrugated Panel
  • Counter Batten
    Vertical wood strips installed on sloped roof over which horizontal battens are secured. The primary roof covering is attached or secured to these horizontal battens. See Batten.
  • Counter Flashing
    Formed metal sheeting secured on or into a wall, curb, pipe, rooftop unit, or other surface, to cover and to help prevent water from migrating behind the base flashing. See Flashing.
  • Course
    A term for a row of shingles or roll roofing running the length of the roof.
  • 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 90º angle.
  • Cover Plate
    A metal strip sometimes installed over the joint between formed metal pieces.
  • Coverage
    The surface area covered by a specific quantity of a roofing material.
  • CPE
    Thermoplastic material, used for single-ply roof membranes, composed of high molecular weight polyethylene which has been chlorinated - a process that yields a flexible rubber-like material.
  • Crack
    A non-linear separation or fracture occurring in a material. May be generally caused by induced stress, dimensional instability, or substrate movement. Some cracks may be more of a linear separation or fracture.
  • Crazing
    A term to describe the surface deterioration of a shingle by the formation of pattern of fine cracks.
  • Creep
    The term for a permanent deformation of a roofing material or roof system caused by movement of the roof membrane, or compression of a roof insulation board at fastener positions, that results from continuous load or thermal stress or loading.
  • Cricket
    An elevated roof substrate or structure, constructed to divert water around a chimney, curb, away from a wall, expansion joint, or other penetration.
  • Cross Ventilation
    The effect that is provided when air moves through a roof cavity between the vents.
  • CSPE,CSM
    Synthetic, rubber-like thermoset material, based on high molecular weight polyethylene with sulphonyl chloride, usually formulated to produce a self-vulcanizing membrane.
  • Cu
    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 is a natural weathering metal used in metal roofing that turns a greenish color after being exposed to the weather for a length of time.
  • Cupola
    A relatively small roofed structure, generally set on the ridge or peak of a main roof area. Commonly used for decoration purposes.
  • Curb
    A raised member used to support roof penetrations, such as skylights, mechanical equipment, hatches, etc., above the level of the roof surface. Commonly made of wood, metal, or plastic.
  • Cure
    A process whereby a material is caused to form permanent molecular linkages by exposure to chemicals, heat, pressure, and/or weathering.
  • Cure Time
    The time required for a material to reach its desirable long-term physical characteristics.
  • Cutoff
    A permanent detail designed to seal and prevent lateral water movement in an insulation system and used to isolate sections of a roofing system.
  • Cutout
    The open portions of a strip shingle between the tabs.
  • d

  • D-Edge
  • Damp proofing
    Treatment of a surface or structure to resist the passage of water in the absence of hydrostatic pressure.
  • Damper
    An adjustable plate for controlling draft.
  • Dead Level
    A horizontal or flat roof deck or rooftop with no intentional slope to the roof drains.
  • Dead Loads
    Permanent non-moving loads that result from the weight of a building’s structural and architectural components, mechanical and electrical equipment, and the roof assembly itself. Also known as dead weight.
  • Deck
    The surface installed over the supporting framing members to which the roofing is applied. Decks are either non-combustible or combustible and provide the substrate to which the roofing or waterproofing system is applied.
  • Decomposition
    The process of rotting; decay.
  • Deflection
    The downward displacement of a structural member or system under load.
  • Degradation
    A loss of strength, cohesion, dissolution, change in the chemical structure, physical properties, and/or appearance of a material due to natural or artificial exposure to radiation, moisture, heat, freezing, wind, ozone, oxygen, etc.; or consumption by living organisms, and erosion or(...)
  • Delamination
    The separation of the layers of a composite material or system; as a result of repeated stress, or failure of the adhesive.
  • Design Loads
    Those loads specified in building codes or standards published by federal, state, county or city agencies, or in owner’s specifications to be used in the design of a building.
  • Dew Point
    The temperature at which water vapor condenses in cooling air at the existing atmospheric pressure and vapor content. Cooling at or below the dew point will cause condensation.
  • Diffusion
    The movement of water vapor from regions of high concentration (high water vapor pressure) toward regions of lower concentration (due to random thermal molecular motion).
  • Dimensional Shingles
  • Direct Nailing
  • Dome
    A roof that is shaped like a half-circle, or variation of one.
  • Dormer
    A framed window unit projecting through the sloping plane of a roof.
  • Dormer Flashing
  • Double Layer
    Installed roofing materials so that there is twice the materials used resulting in a double layer of roofing; or installing a additional layer of roof covering on one layer of existing roof.
  • Downspout
    A pipe for draining water from roof gutters.
  • Drain
    Outlet or other device used to collect and direct the flow of run-off water from a roof area.
  • Drip Caps
  • Drip Edge Flashing
    Roofing component Commonly made of metal, along the eaves of roof to help protect the underlying materials from water backup. See Flashing.
  • Dry-In
    The process of installing the underlayment in steep slope roofing or making a low-slope roof watertight but does not mean getting all of the required plies installed on the low slope roof.
  • Dry Rot
    The effect of build up from condensation, 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.
  • Dynamic Load
    See Wind Loads.
  • e

  • Eave
    The horizontal, lowest edge of a sloped roof that extends beyond the exterior wall.
  • Eave Closure
  • Eave Flashing
    See Drip Edge Flashing.
  • ECH
    A synthetic rubber including two epichlorohydrin based elastomers. It is like and compatible with EPDM. ECH is typically used in lieu of EPDM when enhanced resistance to animal fat or other oils is needed.
  • Edge Riser
    Used to elevate the eave course of roof tiles to the proper height and block birds and vermin from the roofing system. Available in vented or with weeping holes. Provides protected openings along a roof edge or perimeter. The vented riser is used as part of a ventilation system to dissipate(...)
  • Edge Stripping
    Membrane flashing strips cut to specific widths used to seal/flash perimeter edge metal and the roof membrane.
  • Edge Wrinkle
  • Edging Strips
    Boards nailed along eaves and rakes after cutting back existing wood shingles to provide secure edges for reroofing with asphalt shingles.
  • Efflorescence
    The formulation of crystalline deposits, generally whitish in color, on the surface of stone, brick, concrete, or other masonry surface when moisture moves through and evaporates on the masonry. May also be caused by free alkalis leached from mortar, grout, or adjacent concrete.
  • EIP
    A group of thermoplastic compounds generally based on PVC polymers.
  • Elastic Buckling
  • Elasticity
    The property of matter by which it tends to return to its original size and shape after removal of a stress or force, which caused a deformation.
  • Elastomeric
    The rubber-like properties of a material that will stretch when pulled and will return relatively quickly to its original shape when released.
  • Elastomeric Coating
    A coating system which, when fully cured, is capable of being stretched at least twice its original length (100% elongation) and recovering to its original dimensions.
  • Elongation
    The ability of a material, such as roofing membrane, to be stretched by the application of a force.
  • Embedment
    The process of installing or pressing-in reinforcement felt, fabric, mat or panel uniformly into bitumen or adhesive; or the process of pressing granules into coating during the manufacture of factory-prepared roofing; or the process whereby sheet, aggregate, or other roofing components settle(...)
  • EMC
    The moisture content of a material stabilized at a given temperature and content relative humidity, expressed as percent moisture by weight; or the typical moisture content of a material in any given geographical area.
  • Emulsion
    A dispersion of fine particles or globules in a liquid.
  • End Lap
    The distance of overlap where one ply, panel, or piece extends beyond the end of the immediately adjacent underlying ply, panel, or piece.
  • Envelope (Bitumen-Stop)
    A continuous edge seal formed at the perimeter and at penetrations by extending the base sheet or one ply of felt beyond the edge of the membrane field plies. After all overlying field insulation are in place, the extended ply is turned back onto the membrane and adhered. The envelope is(...)
  • EPA
    Government agency whos mission is to help protect human health and the environment.
  • EPDM
    A synthetic rubber elastomer. The compound generally has a high ratio of ethylene in its composition, giving it superior mixing and extrusion properties.
  • Epichlorohydrin
    A synthetic rubber including two epichlorohydrin based elastomers. It is like and compatible with EPDM. ECH is typically used in lieu of EPDM when enhanced resistance to animal fat or other oils is needed.
  • Epoxy
    A class of synthetic, thermosetting resins that produce tough, hard, chemical-resistant coatings and adhesives.
  • Equilibrium Moisture
    The moisture content of a material stabilized at a given temperature and content relative humidity, expressed as percent moisture by weight; or the typical moisture content of a material in any given geographical area.
  • Ethylene
    A flammable hydrocarbon gas of the alkene series, occurring in natural gas, coal gas, and crude oil and given off by ripening fruit.
  • Ethylene Interpolymer
    A group of thermoplastic compounds generally based on PVC polymers.
  • Ethylene Propylene Diene Monomer
    A synthetic rubber elastomer. The compound generally has a high ratio of ethylene in its composition, giving it superior mixing and extrusion properties.
  • Exhaust Vent
    See Goose Neck Vent.
  • Expansion Cleat
    A cleat designed to handle thermal movement of the metal roof panels.
  • Expansion Joint
    A structural separation between two building elements that allows free movement between the elements without damage to the roofing or waterproofing system.
  • Exposed Nail Method
    Application of roll roofing in which all nails are driven into the cemented, overlapping course of roofing; or application of metal roofing in which nails are driven into the metal roof panels. Nails are exposed to the weather. Not to be confused with Face Nailing.
  • Exposure
    Roofing covering that is not covered or overlapped by the installed up the roof slope covering.
  • Extrusion
    A manufacturing process which consists of forcing batched and formulated material (which may be molten) through an orifice called a “die.” The shape and dimensions of the orifice determine the shape and dimensions of the finished product. Extrusion is one method by which some single-ply(...)
  • Eyebrow
    A small shed roof projecting from the gable end of the larger, main roof area or wall area, typically in an arched curved.
  • f

  • Fabric
    A woven cloth or material of organic filaments, threads, or yarns used for reinforcement in certain membranes and flashings.
  • Face Nailing
    Nailing a nail directly into the face, or flat part of the piece of wood or material, at a perpendicular angle to the material into which the nail will sink. Also known as Direct Nailing.
  • Factory Mutual
    A research and testing organization that classifies roofing components and assemblies for their fire, traffic, impact (hail), weathering, and wind uplift resistance for four major insurance companies in the United States.
  • Factory Mutual Research Corp.
    Nationally Recognized Testing Laboratory (NRTL) provides FM Approval for products based on their five-step process that has been provided to OSHA.
  • Factory Seam
    A splice or seam made by the manufacturer during the assembly of sections of materials into large sheets.
  • Fading
    The term for lightening of the initial color, losing brightness, or diming of color.
  • Fancy-Butt shingles
    A wood shingle that come in a wide variety of shapes and are great for decorative accents.
  • Fascia Board
    A vertical roof board located at the perimeter of a building. It can border the low-slope roof system that waterproofs the interior portions of the building. Commonly made of a wood. Covering the joint between the roof and the eaves.
  • Fascia Trim
    A protective or decorative component commonly made of aluminum or plastic that is added to the exposed Fascia Board.
  • Fasteners
    Any of a wide variety of mechanical securement devices and assemblies, such as nails, screws, cleats, clips, and bolts, which may be used to secure two or more objects together.
  • Feathering strips
    Tapered wood filler strips placed along the butts of old wood shingles to create a level surface when reroofing over existing wood shingle roofs.
  • Felt
    A fibrous sheet manufactured by the interlocking of fibers through a combination of mechanical work, moisture, and heat. Roofing felts may be manufactured principally from wood pulp and vegetable fibers (organic felts), asbestos fibers (asbestos felts), glass fibers (fiberglass felts or ply(...)
  • Ferrule
    A sleeve used as a spacer to keep gutter from being battered when secured to fascia with spikes.
  • Fiberglass Insulation
    Blanket or rigid board insulation, composed of glass fibers bound together with a binder, faced or unfaced, used to insulate roofs and walls. Rigid boards usually have an asphalt and kraft paper facer.
  • Fiberglass Mat
    A thin mat composed of glass fibers, woven or non-woven, with or without a binder. This mat may serve as reinforcement for certain roof materials and membranes.
  • Field of the Roof
    The central or main portion of a roof, excluding the perimeter and flashing.
  • 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 90º angles.
  • Fin
    A term for a sharp protrusion in a roof deck that can damage roof components.
  • Fire Wall
    Any wall built for the purpose of restricting the spread of fire in a building. Such walls of solid masonry or concrete usually divide a building from the foundations to about a meter above the roof.
  • Fish-mouth
    A half-cylindrical or half-conical shaped opening or void in a lapped edge or seam, usually caused by wrinkling or shifting of ply sheets during installation; or in shingles, a half-conical opening formed at a cut edge.
  • Flaking
    Detachment of a uniform layer of a coating or surface material, usually related to internal movement, lack of adhesion, or passage of moisture. Occurs when a coating loses its cohesion.
  • Flange
    The projecting edge of a rigid or semi-rigid component, such as a metal edge flashing flange, skylight flange, flashing boot, structural member, etc.
  • Flash
    To install flashing components.
  • Flash Point
    The lowest temperature of a liquid at which it gives off vapors sufficient to form an ignitable mixture with air near its surface.
  • Flashing
    Components the can be made of metal, plastic, or cap sheet; used to weatherproof or seal the roof system edges at perimeters, penetrations, walls, expansion joints, valley, drains, chimney and other places where the roof covering is interrupted or terminated.
  • Flashing Cement
    A spreadable mixture of solvent-based bitumen and mineral stabilizers that may include asbestos or other inorganic or organic fibers. Generally, flashing cement is characterized as vertical-grade, which indicates it is intended for use on vertical surfaces.
  • Flashing Collar
    Used to seal soil pipe vents, hot stacks or other roof penetrations See Pipe Boot.
  • Flat Lock
    A method of interlocking metal panels in which one panel edge is folded back on top of itself and the other panel is folded under, after which the two panels are hooked together.
  • Flood Coat
    The surfacing layer of bitumen into which surfacing aggregate is embedded on an aggregate-surfaced built-up roof. A flood coat is generally thicker and heavier than a glaze coat and is applied at approximately 45-60 pounds per square.
  • Flood Test
    A water exam performed to determine the effectiveness of a roof covering.
  • Fluid Applied Elastomer
    A liquid elastomeric material that cures after application to form a continuous waterproofing membrane.
  • FM
    A research and testing organization that classifies roofing components and assemblies for their fire, traffic, impact (hail), weathering, and wind uplift resistance for four major insurance companies in the United States.
  • g

  • Gable
    The upper portion of a sidewall that comes to a triangular point at the ridge of a sloping roof.
  • Gable-On-Hip Roof
    A roof configuration with hips coming up from the eave corners that terminate into a gable roof.
  • Gable Roof
    A type of roof framing style containing a sloping plane on each side of a single ridge with a gable at each end
  • Gable Vent
    Comes in several shapes with screening attached on the inside, a louvered design, and are in the front of the gable roof near the top and are meant to allow air flow through the gable roof. Can be a decorative exterior item. Electric fans can be attached to them as well.
  • Galvalume ®
    A trade name for a coating, used over metal, that is composed of aluminum zinc for corrosion protection.
  • Galvanized
    The application of zinc.
  • Galvanized Steel
    Steel coated with zinc for corrosion resistance.
  • Gambrel Roof
    A type of roof framing style containing two sloping planes of different pitch on each side of the ridge. The lower plane has a steeper slope than the upper. Features a gable at each end. Like “Barn” style roof.
  • Girt
    A horizontal beam place between support columns that is used for attaching wall cladding.
  • Glass Felt
    A sheet composed of bonded glass fibers, suitable for filling and coating in the manufacture of bituminous roofing and waterproofing materials, and shingles.
  • Glaze Coat
    The top layer of asphalt on a smooth-surfaced built-up roof membrane; or a thin protective coating of bitumen applied to the lower plies or top ply of a built-up roof membrane when application of additional felts or the flood coat and aggregate surfacing are delayed.
  • Goose Neck Vent
    A gooseneck is a preformed angled pipe fitting covering used to prevent water around a duct or kitchen pipe penetration from roof. Its name comes how the bend in the vent is like the bend in a gooses’ neck and is designed with a screen to help prevent rodents.
  • Grain
    Unit used to measure the mass of moisture.
  • Granule
    Opaque, natural, or synthetically colored aggregate commonly used to surface cap sheets, shingles, and other granule-surfaced roof coverings.
  • Gravel
    Aggregate resulting from the natural erosion of rock. See Aggregate.
  • Gravel Stop
    A low profile upward-projecting metal edge flashing with a flange along the roof side, usually formed from sheet or extruded metal. Installed along the perimeter of a roof to provide a continuous finished edge for roofing material.
  • Grout
    A thin mortar used to fill cracks in masonry and tile.
  • Gutter
    The trough that channels water from the eaves to the downspouts.
  • Gutter Apron
  • h

  • Headlap
    The distance of overlap measured from the uppermost ply or course to the point that it laps over the undermost ply or course.
  • Hem
    The edge created by folding metal back on itself.
  • HEX Shingles
    Shingles that have the appearance of a hexagon after installation.
  • High Nailed
    The term for when shingles are fastened above the manufacturer’s recommended location.
  • Hip
    Inclined external angle formed by the intersection of two sloping roof planes.
  • Hip and Ridge Metal Support Frame
    Used with tile roofing material on the hips and/or ridge of roof. Roofing Tile Cap to be installed on top with manufacture approved products.
  • Hip Roof
    A type of roof framing style containing sloping planes of the same pitch on each of four sides. Contains no gables.
  • Hip Shingles
    Shingles used to cover the inclined external angle formed by the intersection of two sloping roof planes. See Ridge Cap.
  • Hoist
    A mechanical lifting device. A hoist can be hand or electrically operated.
  • Homogeneous
    The term for the same kind; or alike.
  • Horsefeathers
  • HVAC
    Heating, ventilating, and air conditioning equipment.
  • Hybrid Modified
    Combination of Hot and Cold application
  • Hydrostatic
    Relating to or denoting the equilibrium of liquids and the pressure exerted by liquid at rest.
  • i

  • I-Beam
    A structural support beam commonly used in civil engineering and construction. Commonly made of metal
  • Impact Resistance
    The term for a roof assembly's ability to withstand the impact from falling objects such as hail. Subject to different ratings.
  • Incline
    The slope of a roof expressed either in percent or in the number of vertical units of rise per horizontal units of run. See Slope.
  • Infrared Thermography
    A practice of roof system analysis where an infrared camera is used to measure the temperature differential of a roof surface to locate areas of underlying wet or moist insulation. Also known as Thermal Image.
  • Inorganic
    Any chemical or compound that is derived from minerals, does not contain carbon, and is not classified as organic; being or composed of materials other than hydrocarbon’s and their derivatives; not of plant or animal origin.
  • Insulation
    Any of a variety of materials designed to reduce the flow of heat, either from or into a building.
  • Intake Vent
    See Eave Vent or Soffit Vent.
  • Interlayment
    A felt, metal, or membrane sheet material used between courses of steep-slope roofing to improve the weather and water-shedding characteristics of the primary roof covering during times of wind-driven rain and snow. Typically used with wood shakes.
  • Interlocking Shingles
    Individual shingles that mechanically fasten to each other to provide wind resistance.
  • Internal Pressure
    Pressure inside a building that is a function of ventilating equipment, wind velocity, and the number and location of openings and air leaks.
  • Isocyanate
    A highly organic chemical containing one or more isocyanate (-N=C=0) groups. A basic component in SPF based systems and some polyurethane coating systems.
  • j

  • Jack
  • Joint Tape
    Tape used to seal joints between insulation boards.
  • Joist
    Any of the small timbers, metal or wood beams arranged parallel from wall to wall to support a floor, ceiling, or roof of a building.
  • k

  • k
    The heat energy that will be transmitted by conduction through 1 square foot of 1-inch thick homogeneous material in one hour when there is a difference of 1-degree Fahrenheit perpendicularly across the two surfaces of the material. The formula for thermal conductivity is: k=Btu/Square(...)
  • Knee Cap
    A metal cover trim that fits over a panel rib after it has been cut and bent.
  • l

  • L-Flashing
  • Laminated Shingles
    Asphalt shingle that provides a dimensional appearance without tabs or cutouts. Strip shingles containing more than one layer of tabs to create extra thickness.
  • Lap
    The part of a roofing, waterproofing, or flashing component that overlaps or covers any portion of the same or another type of adjacent component.
  • Lap Cement
  • Lap Seam
    Occurs where overlapping materials are seamed, sealed or otherwise bonded.
  • Lateral Wind Load
    A pulling and pushing horizontal pressure that can cause a building to move off its foundation. See Wind Loads.
  • Latex
    A colloidal dispersion of a polymer or elastomer in water which coagulates into a film upon evaporation of the water.
  • Lead
    A soft workable metal used for miscellaneous flashings.
  • Leader Head
  • Lichens
    A leafy looking composite organism, green-gray in color, that can grow on top of roofs. They are not plants. Lichen can hold moisture against the surface; speeding up wear and tear that can shorten the life of your roof.
  • Live Loads
    Temporary loads that the roof structure must be designed to support, as required by governing building codes. Live loads are generally moving and/or dynamic or environmental (e.g., people, installation equipment, wind, snow, ice or rain, etc.).
  • Loose-Laid Membranes
    Membranes that are not attached to the substrate except at the perimeter of the roof and at penetrations. Typically, loose laid membranes are held in place with ballast, such as water-worn stone, gravel, pavers, etc.
  • Louver
    A slanted opening for ventilation.
  • Low Slope Roofing
    A roofing system with a slope of 2:12, 3:12, or 4:12 of run. These roofs have water run off or drains water more slowly than moderate or steep sloped roofs.
  • Low Slope Shingle Application
    Method of installing asphalt shingles on roof slopes between three and four inches per foot.
  • m

  • Mansard Roof
    A decorative steep-slope roof framing style along the perimeter of a building that terminates into a flat roof at its high point.
  • Masonry Primer
    An asphalt-based primer used to prepare masonry surfaces for bonding with other asphalt products.
  • Mastic
  • 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.
  • Mechanically-Fastened Membranes
    Generally used to describe membranes that have been attached at defined intervals to the substrate. Mechanically fastening may be performed with various fasteners and/or other mechanical devices, such as plates or battens.
  • Membrane
    A flexible or semi-flexible material, which functions as the waterproofing component in a roofing or waterproofing assembly, and whose primary function is the exclusion of water.
  • Meter
    Unit of length measurement in the metric system, equal to 39.37 inches.
  • Mil
    A unit of measure, one mil is equal to 0.001 inches, often used to indicate the thickness of a roofing membrane.
  • Mildew
    A superficial coating or discoloring of an organic material due to fungal growth, especially under damp conditions.
  • Mineral Fiber
    Inorganic fibers of glass, asbestos, or rock (mineral wool).
  • Mineral Stabilizer
    A fine, water-insoluble inorganic material, used in a mixture with solid or semisolid bituminous materials.
  • Mineral Surfaced Roofing
    Roofing materials whose surface or top layer consists of mineral granules.
  • Mineral-Surfaced Sheet
    A roofing sheet that is coated on one or both sides with asphalt and surfaced with mineral granules.
  • Miter
    The joint produced by joining two diagonally cut pieces.
  • Moderate Slope Application
    A roofing system with a slope of 5:12, 6:12, or 7:12 of run. These roofs have water run off or drains water with an average rate and can be walked on without mechanical device or assistance.
  • Modified Bitumen
    A heavy roofing material employing multiple layers of asphalt and reinforcers around a core of plastic or rubber modifiers. Installed with a special torching apparatus, a cold adhesive or hot mopped into place using methods of asphalt application.
  • Moisture Relief Vent
    A venting device installed through the roofing membrane to relieve moisture vapor pressure from within the roofing system.
  • Moisture Scan
    The use of a device to perform a non-destructive test to detect the presence of moisture within a roof assembly.
  • Mole Run
    A term used to describe a ridge in a roof membrane that is not the result of improper deck or insulation joints.
  • Mortar
    Mix is a mixture of high strength masonry cement and sand designed as the adhesive for the installation of roof tiles.
  • Moss
    A small flowerless plant that typically grow in dense green clumps often in damp or shady locations. Moss can cause premature deterioration of roofing materials.
  • Mud Cracking
    The term used to describe the surface cracking of a material that looks similar to dried, cracked mud.
  • n

  • Nail Pop
  • Nailing
    The application of nails or fasteners.
  • Nationally Recognized Testing Laboratory
    A term used by the United States Occupational Safety and Health Administration to identify third-party organizations that have the necessary qualifications to perform safety testing and certification of products covered within OSHA and each organization's scopes.
  • Natural Ventilation
    A ventilation system utilizing ventilators installed in openings in the attic and properly positioned to take advantage of natural air flow to draw hot summer or moist winter air out and replace it with fresh outside air.
  • Neoprene
    A synthetic rubber (polychloroprene) used in liquid-applied and sheet-applied elastomeric roof membranes, fasteners, or flashings.
  • Nesting
    A method of recovering with new asphalt shingles over existing shingles in which the top edge of the new shingle is butted against the bottom edge of the existing shingle.
  • No-cutout Shingles
    Shingles consisting of a single, solid tab with no cutouts.
  • Non-Friable
    A material that, when dry, cannot be crumbled, pulverized or reduced to powder by hand pressure.
  • Non-Oxidizing
    For waterproofing purposes, a membrane system requiring some form of protection barrier and wearing surface.
  • Non-Traffic Bearing
    A term used for waterproofing proofing or membrane system intended for weather exposure as primary roof. Such systems are commonly made of a single-ply system. They are not acceptable for traffic.
  • Non-Vulcanized Membrane:
    A membrane manufactured from thermoplastic compounds that retains its thermoplastic properties throughout the service life of the membrane.
  • Nonwoven
    A term used to describe the random arrangement of reinforcing fibers such as glass, polyester, etc., in a mat or scrim.
  • NRTL
    A term used by the United States Occupational Safety and Health Administration to identify third-party organizations that have the necessary qualifications to perform safety testing and certification of products covered within OSHA and each organization's scopes.
  • o

  • Occupational Safety and Health Administration
    An agency of the United States Department of Labor.
  • Off Ridge Vent
    Vent that can be used as an air exhaust near top of steep slope roofs or intake vent when installed on a low sloped roof near the bottom. This vent has a low-profile design with an internal screen protects against unwanted pests. Traditionally installed just below the ridge of a roof giving it(...)
  • Offset Flashing
  • Oil Canning
    A term used in metal roofing to describe visible waviness in flat areas of metal roofing or metal wall panels. The degree of waviness can be difficult to measure, but may be apparent, under certain lighting conditions.
  • Open Valley
    A method of valley construction in which the steep-slope roofing on both sides is trimmed along each side of the valley, exposing the valley flashing.
  • Orange Peel
    A term used for a surface that shows a fine texture and is compared to the exterior skin of a surface texture orange. This surface is considered acceptable for receiving a protective coating.
  • Organic
    Being or composed of hydrocarbons or their derivatives originating from plant or animal matter.
  • Organic Felt
    An asphalt shingle reinforced with material manufactured form cellulose fibers.
  • Organic Shingle
    An asphalt shingle reinforced with material manufactured form cellulose fibers.
  • Oriented Strand Board
    Wood decking made from wood chips and lamination Glue.
  • OSB
    Wood decking made from wood chips and lamination Glue.
  • OSHA
    An agency of the United States Department of Labor.
  • Over Driven
    A term used for fasteners driven into roofing material with too much force.
  • Overhang
    That portion of the roof structure that extends beyond the exterior walls of a building; or roofing material over the edge of roof.
  • Oxidization
    The deposit that forms on the surface, commonly metal, as it converts an element that combines with oxygen. See Degradation.
  • p

  • Pallet
    Wooden platforms used for storing and shipping bundles of shingles.
  • Pan
    The bottom flat part of a roofing panel which is between the ribs of the panel.
  • Parapet Wall
    That part of a perimeter wall immediately adjacent to the roof which extends above the roof.
  • Partially-Attached
    A roofing assembly in which the membrane has been “spot fixed” to a substrate, usually with an adhesive or a mechanical device.
  • Peel Strength
    The average force (or force per unit width) required to peel a membrane or other material from the substrate to which it has been bonded.
  • Penetration
    An object passing through the roof.
  • Percent Elongation
    In tensile testing, the increase in the gauge length of a specimen measured at or after fracture of the specimen within the gauge length. Usually expressed as a percentage of the original gauge length.
  • Perlite
    An aggregate used in lightweight insulating concrete and in preformed perlitic insulation boards, formed by heating and expanding siliceous volcanic glass.
  • Perm
    A unit of water vapor transmission defined as 1 grain of water vapor per square foot per hour per inch of mercury pressure difference.
  • Permeability
    The capacity of a porous material to conduct or transmit fluids; or the amount of a fluid moving through a barrier in a unit time, unit area, and unit pressure gradient not normalized for, but directly related to, thickness.
  • Permeance
    The rate of water vapor transmission per unit area at a steady state through a material, membrane or assembly.
  • Phased Application
    The application of installation of separate roof system or waterproofing system component(s) during two or more separate time intervals. Application of surfacing at different time intervals is typically not considered phased application.
  • Philadelphia Flashing
  • Philly Flashing
    Also known as Philadelphia Flashing. See Flashing.
  • PIB
    A product formed by the polymerization of isobutylene. May be compounded for use as a roof membrane material.
  • Picture Framing
    A square or rectangular pattern of buckles or ridges in a roof covering generally coinciding with insulation or deck joints; generally, a function of movement of the substrate.
  • Pinhole
    A small hole in a coating, foil, membrane, or other roofing material.
  • Pipe Boot
    Prefabricated flashing piece used to flash around circular pipe penetrations. Usually made of lead. Also known as a Flashing Collar or Boot Pipe Flashing.
  • Pitch
    The degree of roof incline expressed as the ratio of the rise, in feet, to the span, in feet or a short term for Coal Tar Pitch material. See Slope.
  • Pitch Pan
    A flanged, open bottomed enclosure made of sheet metal or other material, placed around a penetration through the roof, filled with grout and bituminous or polymeric sealants to seal the area around the penetration.
  • Pitch Pocket
  • Pittsburgh Lock Seam
    A method of interlocking metal, usually at a slope change.
  • Plastic Cement
    A term in roofing industry generic used to describe Type l asphalt roof cement that is a spreadable mixture of solvent-based bitumen, mineral stabilizers, other fibers and/or fillers.
  • Pliability
    The material property of being flexible or moldable.
  • Ply
    A layer of felt, ply sheet, or reinforcement in a roof membrane or roof system; or the number of layers of roofing; or the term for wood that is made of several layers of thin wood sheets to make a board.
  • PMR
    An insulated and ballasted roofing assembly, in which the insulation and ballast roof are applied on top of the membrane (sometimes referred to as an “inverted roof assembly”).
  • Poly Foam Roofing
  • Polyisobutylene
    A product formed by the polymerization of isobutylene. May be compounded for use as a roof membrane material.
  • Polymer
    A natural or synthetic chemical compound of high molecular weight, or a mixture of such compounds, formed when monomers (small individual molecules) are combined to form large long-chain molecules.
  • Polypropylene
    A tough, lightweight plastic made by the polymerization of high-purity propylene gas.
  • Polyvinyl Chloride
    A synthetic thermoplastic polymer prepared from vinyl chloride. PVC can be impounded into flexible and rigid forms using 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 relatively small headed pin with an expandable head for joining relatively light gauge metal.
  • Positive Drainage
    The drainage condition in which consideration has been made during design for all loading deflections of the deck, and additional roof slope has been provided to ensure drainage of the roof area within 48 hours after the last rainfall, during ambient drying conditions.
  • Pourable Sealer
    A type of sealant often supplied in two parts and used at difficult-to-flash penetrations, typically in conjunction with pitch-pockets to form a seal.
  • Primer
    A thin, liquid-applied solvent-based bitumen that may be applied to a surface to improve the adhesion of subsequent applications of bitumen; or a material which is sometimes used in the process of seaming single-ply membranes to prepare the surfaces and increase the strength (in shear and(...)
  • Protected Membrane
    An insulated and ballasted roofing assembly, in which the insulation and ballast roof are applied on top of the membrane (sometimes referred to as an “inverted roof assembly”).
  • Puncture Resistance
    A term to describe to which a material can withstand the action of a sharp object without perforation.
  • Purlin
    Horizontal secondary structural member that transfers loads from the primary structural framing.
  • PVC
    A synthetic thermoplastic polymer prepared from vinyl chloride. PVC can be impounded into flexible and rigid forms using 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.
  • Pyramid Hip Roof
    A type of roof framing style containing sloping planes of the same pitch on each of four sides. They are composed four triangles side or two triangulars sides and two trapezoidal sides. It has four front that have a similar slope. Contains no gables.
  • r

  • R
    Index of a material’s resistance to heat flow; it is the reciprocal of thermal conductivity (k) or thermal conductance (C). The formula for thermal resistance is: R= 1 or R = 1 or R= Thickness in inches.
  • R-Value
    The resistance to heat transfer of a material.
  • Racking
    A method of tab asphalt shingle application, also referred to as the straight-up method. The shingles are applied going vertically up the roof not diagonally or laterally.
  • Rafter
    One of a series of sloped structural members that extend from the ridge or hip to the wall plate, downslope perimeter or eave, and that are designed to support the roof deck and its associated loads. Commonly made from steel or wood.
  • Raggle
    A groove or slot, often cut in a masonry wall or other vertical surface adjoining a roof, for inserting an inset flashing component such as a Reglet.
  • Rain Diverter
    Used to direct water away from your doorway and/or into gutters. Commonly made of metal.
  • Rake
    The sloped edge of a roof at or adjacent to the first or last rafter.
  • Rake Starter
  • Random-tab shingles
    Shingles on which tabs vary in size and exposure.
  • Re-Cover
    The application of a new roof membrane or steep-slope roof covering over a major portion of an existing roof assembly. This process does not involve removal of the existing roof.
  • Reglet Flashing
    A sheet metal receiver for the attachment of counterflashing, may be inset into a raggle, embedded behind cladding, or be surface mounted. See Flashing.
  • Reinforced Membrane
    A roofing or waterproofing membrane that has been strengthened by the addition or incorporation of one or more reinforcing materials, including woven or nonwoven glass fibers, polyester mats or scrims, nylon, or polyethylene sheeting.
  • Relative Humidity
    The ratio of the weight of moisture in a given volume of air-vapor mixture to the saturated (maximum) weight of water vapor at the same temperature, expressed as a percentage. (For example, if the weight of the moist air is 1 pound and if the air could hold 2 pounds of water vapor at the same(...)
  • Release Tape
    A plastic film or paper strip that is applied to the back of self-sealing shingles and other materials. The strip prevents the material from sticking together in the roll or bundle. With asphalt shingles, the strip IS NOT to be removed for application of the shingles.
  • Replacement
    The practice of removing an existing roof material as described and replacing it with a new roofing material as described. See Reroofing for Roof Replacement.
  • Reroofing
    The process of tearing off and replacing an existing roof system.
  • Resistance
    Loss of elasticity caused by the alternating stretching and relaxing of the material over a period.
  • Ribbed Tile Pan Flashing
    Metal formed with double ribs to elevate tile and battens above water flow area. Used with tile over underlayment, under battens at wall intersection. See Flashing.
  • Ridge
    Highest point on the roof, represented by a horizontal line where two roof areas intersect, running the length of the area.
  • Ridge Cap
    A material or covering applied over the ridge line.
  • Ridge Course
  • Ridge Line
    The last or top course of roofing materials, such as tile, roll roofing, shingles, etc., that covers the ridge and overlaps the intersecting field roofing. Also known as Ridge Course.
  • Ridge Riser
    Used to elevate the ridge tile to enhance ridge ventilation. Commonly made of a preformed metal, used with ridge board.
  • Ridge Vent
    A vent that provide uniform cooling along the roof deck, installed over the ridge of the roof in place of roof cap to provide an exhaust vent from the peck of the roof line. Usually made of metal, however plastic is available with use of Ridge Cap Shingles for decoration purpose.
  • Ring Shank Nails
    Annual threads or "rings" are formed on the shank of the nail to increase withdrawal capacity. The "rings" provide friction to help prevent the nail from backing out over time. Generally considered the nail type with the best withdrawal resistance. See Fasteners.
  • Rise
    The vertical distance from the eaves line to the ridge.
  • Roll Roofing
    A general term used to describe a smooth or mineral surface, or underlayment materials that are manufactured on a roll.
  • Roof Assembly
    An assembly of interacting roof components which can include the roof deck, vapor retarder (if present), insulation (if present) and roof covering.
  • Roof Bracing
    Diagonal metal rods or cables and struts supporting the resisting tension faces of the frame members. The struts are designed for compression.
  • Roof Covering
    The exterior roof material or skin of the roof assembly, consisting of membrane, panels, sheets, shingles, tiles, etc.
  • Roof Diaphragm
    Constructed by either Roof bracing or Roof Decking.
  • Roof Jack
    A metal bracket used to support toe-boards on steep-slope roofs
  • Roof Over
  • Roof Pitch
    See Slope.
  • Roof Seamer
    Device that crimps neighboring metal roof panels together or that welds laps of membrane sheets together using heat, solvent, or dielectric energy.
  • Roof System
    A system of interacting roof components, generally consisting of membrane or primary roof covering and insulation (not including the roof deck) designed to weatherproof and, sometimes, to improve the building’s thermal resistance.
  • Roof Void
    An open space or break in consistency.
  • Roofer
    A crafts person whose profession is to remove and install roofing material.
  • Roofing Cement
  • Roofing Nail
    Commonly short nails of a heavy gauge with a wide round head. Used for fastening roofing materials such as shingles to roof deck. Commonly coated to prevent rust. See Fasteners.
  • Rosin Paper
    A non-asphaltic paper used as a sheathing paper or slip sheet in some roof systems.
  • Rubber
    A polymeric material which, at room temperature, can recover substantially in shape and size after removal of force. May be natural or synthetic.
  • Run
    The horizontal distance from the eaves to a point directly under the ridge. One half the span.
  • s

  • SA
    A membrane that can adhere to a substrate and to itself at overlaps without the use of an additional adhesive.
  • Saddle
    A relatively small raised substrate or structure constructed to channel or direct surface water to drains or off the roof. A saddle may be located between drains or in a valley and is often constructed like a small hip roof or like a pyramid with a diamond-shaped base. See Cricket.
  • Saturated Felt
    A type of felt that has been partially saturated with low softening point bitumen.
  • SB
    High molecular weight polymers having rubber-like properties, formed by the random copolymerization of styrene and butadiene monomers.
  • SBS
    A synthetic rubber based on block copolymers having a rubber center block and two polystyrene end blocks, they combine the properties of a thermoplastic resin with those of butadiene rubber. The hard, glassy styrene blocks provide mechanical strength and improve the abrasion resistance, while(...)
  • Screw Plate
    Used with screws to secure insulation board to substrate. Commonly coated for resistance to corrosion.
  • Screws
    A slender, sharp-pointed metal pin with a raised helical thread running around it and a slotted head, used to join things together by being rotated so that it pierces wood or other material. See Fasteners.
  • Scrim
    A woven, nonwoven, or knitted fabric, composed of continuous strands of material used for reinforcing or strengthening membranes. May be incorporated into a membrane by the laminating or coating process.
  • Scupper
    Roof drainage system that provides drainage of a flat roof by allowing the water runoff from the roof to exit the roof through a metal edge, parapet wall or through the deck into a downspout or leader. Not to be confused with a drain.
  • Scuttle
    A hatch that provides access to the roof from the interior of the building.
  • Seal
    A generic term for a function that helps prevent or helps to control the passage of water.
  • Sealant
    A single or multicomponent polymeric or bituminous material used to weatherproof many types of construction joints where moderate movement is expected. The material in various grades: pourable, self-leveling, non-sag, gun grade, and cured or uncured tapes.
  • Sealing Washer
    A rubber or neoprene washer, sometimes metal-backed, typically assembled on a fastener to prevent water from migrating into and through the fastener hole.
  • Seam
    A joint formed by mating two separate sections of material. Seams may be made or sealed in a variety of ways, including adhesive bonding, hot-air welding, solvent welding, using adhesive tape, sealant, etc.
  • Seam Strength
    The force or stress required to separate or rupture a seam in the membrane material.
  • Self-Adhering Membrane
    A membrane that can adhere to a substrate and to itself at overlaps without the use of an additional adhesive.
  • Self-Drilling Screw
    A fastener that drills and taps its own hole during application.
  • Self-Sealing Cement
    A thermal-sealing tab cement built into the shingle to firmly cement the shingles together automatically after they have been applied properly and exposed to warm sun temperatures. In warm seasons, the seal will be complete in a matter of days. In colder seasons, sealing time depends on the(...)
  • Self-Sealing Shingle
    An asphalt shingle containing factory-applied strip or spots of heat sensitive adhesive intended to adhere to the overlying shingle once installed on the roof and warmed by the sun, without the use of additional adhesive.
  • Self-Tapping Screw
    A fastener that forms receiving threads when turned into a previously drilled hole.
  • Self-Vulcanzied Membrane
    A membrane manufactured from compounds that are thermoplastic during manufacture and installation, but whose polymers eventually cross-link and cure during exposure.
  • Selvage
    An edge or edging that differs from the main part of a fabric, granule-surfaced roll roofing or cap sheet, or other material.
  • Selvage Edge
    An edge designed for certain mineral sheet good materials. With mineral-surfaced sheets, the surfacing is omitted over a portion of the longitudinal edge of the mineral surface sheet cap in order to obtain better adhesion of the overlapping sheet.
  • Shading
    Slight differences in shingle color that may occur because of normal manufacturing operations. Commonly manufacturing at different times color will differ according to different lots of materials. Exact color matching is not possible.
  • Shank
    The middle part or “shaft” between the pointed end and the top or “head” of the nail. Comes in Smooth, Screw, Ring, Barbed, Spiral, Etc., styles. See Fasteners.
  • Shark Fin
    An upward-curled felt side lap or end lap.
  • Shear Strength
    The stress required to disrupt a seam or bonded joint or attachment by forcing the substrate material to slide out from the overlying material or vice versa
  • Shear Wind Load
    Wind pressure that is horizontal and could make a building tilt. See Wind Loads.
  • Sheathing
    See Deck.
  • Shed Roof
    A roof framing style containing only one sloping plane. Has no hips, ridges, valleys or gables.
  • Shiner
    Nail that didn’t get covered by roofing material. Does not include Face-Nail used for exposed fastening roof systems.
  • Shingle
    Individual unit of prepared roofing material. Commonly made of a granule asphalt.
  • Shingling
    The application of shingles; or the procedure of applying shingles or laying parallel felts so that one longitudinal edge of each felt overlaps and the other longitudinal edge of the adjacent shingle or felts underlaps. Felts are commonly shingled from a downslope portion of the roof to the(...)
  • Shrinkage
    A reduction in size.
  • Shrinkage Crack
    A separation in a material, caused by the inability of the material to resist a reduction in size which occurs during its hardening process, curing process, or both.
  • Side Lap
    The continuous longitudinal overlap of neighboring like materials.
  • Side Lap Fastener
    A fastener used to connect adjacent panels together at the side lap.
  • Side Lap-Ganging
    Pattern or application for roofing materials, as related to the amount of cover or side overlap of adjacent like materials.
  • Sieve
    A device with uniform sized opening for separating sizes of material.
  • Sill
    The bottom horizontal framing member of an opening, such as below a window or door.
  • Sill Flashing
    A flashing of the bottom horizontal framing member of an opening, such as below a window or door.
  • Simplex Nails
    A type of capped nail. Cap can be made of metal or plastic. Used to install base sheet, roofing felt, board insulation, recovery board, metal batten, roof membrane, house wraps, or vapor barriers. See Fasteners.
  • Single Coverage
    Roofing material that provides one layer over the substrate to which it is applied.
  • Single-Lock Standing Seam
    A standing seam that utilizes one overlapping interlock between two seams. Commonly used with metal panels.
  • Single-Ply Membranes
    Roofing membranes that are field applied using just one layer of membrane material (either homogeneous or composite) rather than multiple layers.
  • Single-Ply Roofing
    A roofing system in which the principal roof covering is a single layer flexible membrane, often thermoset, thermoplastic, or polymer modified bituminous compounds.1) Fully-adhered 2) Loose-laid 3) Mechanically-fastened 4) Partially-adhered 5) Protected membrane roof 6) Self-adhering; A(...)
  • Single-Ply System
    Generally, there are six types of single-ply roofing systems:
  • Skinning
    The formation of a dense film on the surface of a liquid coating or mastic.
  • Skylight
    A fixed or vented window installed in a roof deck. Commonly transparent with a glaze, can also come with a tint.
  • Slag
    A hard, air-cooled aggregate that is left as a residue from blast furnaces, which may be used as a surfacing material on certain (typically bituminous) roof membrane systems.
  • Slate
    A hard, brittle metamorphic rock consisting mainly of clay materials, used extensively as dimensional stone for steep roofing, and in granular form as surfacing on some other roofing materials.
  • Slip Sheet
    A sheet material, such as reinforced kraft paper, rosin-sized paper, polyester scrim, or polyethylene sheeting, placed between two components of a roof assembly (such as between membrane and insulation or deck) to ensure that no adhesion occurs between them, and to prevent possible damage from(...)
  • Slope
    The angle of incline, usually expressed as a ratio of rise to run, or as a percent. Roof Slope is the angle a roof surface makes with the horizontal, ratio of unit of vertical rise to the units of horizontal length or run. Also known as Roof Pitch.
  • Smooth Surface Roof
    A roof membrane without mineral, granule, or aggregate surfacing. Roof membrane with minimal wave.
  • Snap-On Cap
    A separate cap that snaps on over the vertical legs of some single standing or batten seam metal roof system.
  • Soffit Vent
    The enclosed intake ventilation installed underside of the exterior overhang section of roof eave.
  • Soil Stack
    A sanitation pipe that penetrates the roof.
  • Solar Attic Vent
    A mechanical solar powered roof attic exhaust vent installed in roof deck, no electric needed.
  • Solder
    A lead/tin mixture that is melted and used to bond two pieces of some metals together.
  • Solvent Welding
    A process where a liquid solvent is used to chemically weld or join two or more layers of certain membrane materials (usually thermoplastic).
  • Span
    The horizontal distance from eaves to eaves.
  • Specification
    A term that describes products, materials, and processes to be used. A specification may also contain terms of the contract or statement of requirements for a project.
  • SPF
    A foamed plastic material, formed by spraying two components (isocyanate and Resin) to form a rigid adhered, water resistant, and insulating membrane. Also known as Polyurethane (Poly) Foam Roofing.
  • Splash Block
    A small masonry or polymeric block laid on the ground or lower roof below the opening of a downspout used to help prevent soil erosion and aggregate scour in front of the downspout.
  • Splice
    Bonding or joining of overlapping materials.
  • Split
    A rupture (generally linear) or tear in a material or membrane resulting from tensile forces.
  • Sprayed Polyurethane Foam
    A foamed plastic material, formed by spraying two components (isocyanate and Resin) to form a rigid adhered, water resistant, and insulating membrane. Also known as Polyurethane (Poly) Foam Roofing.
  • Square
    100 square feet (9.29m) of roof area
  • Stainless Steel
    An alloy of steel that contains a high percentage of chromium. Also, may contain nickel or copper. Generally, has very good resistance to corrosion.
  • Standing Seam
    A metal roof system that consists of an overlapping or interlocking seam that occurs at an upturned rib. The standing seam may be made by turning up the edges of two adjacent metal panels and overlapping them, then folding or interlocking them in a variety of ways. See Architectural Metal Panel.
  • Starter Course
    The first layer of roofing, applied along a line adjacent to the downslope perimeter of the roof area. With steep-slope roof coverings, the starter course is covered by the first course.
  • Starter Sheets
    Felt, ply sheet, or membrane strips that are made or cut to widths narrower than the standard width of the roll, used to start the shingling pattern at an edge of the roof; or width sheets designed for perimeters in some mechanically attached and fully adhered single-ply systems.
  • Starter Strip
    Roll roofing or shingle strips applied along the downslope eave line, before application of the first course of roofing, intended to fill spaces between cutouts and joints of the first course.
  • Static Load
    Any load, as on a structure, that does not change in magnitude or position with time.
  • Steel Joist
    Commonly used as a horizontal supporting member between beams or other structural members, suitable for the support of some roof decks.
  • Steep Slope Application
    A roofing system with a slope of 8:12 or above of run. These roofs have fast water runoff and are not walkable without additional devices.
  • Step Flashing
    A metal flashing made of individual pieces of metal used at the intersection of a wall or chimney and a sloping roof. Each piece is installed individually overlapping the stepping up the wall with the horizontal edge complimenting the lines of any brickwork exposed. See Flashing.
  • Stick Clip
    In waterproofing, a non-penetrating fastener that is adhered to the waterproofing surface; typically used to retain insulation, drainage panels, prefabricated protection materials, etc., against the waterproofing to prevent sliding and displacement.
  • Storm Collar
    See Collar.
  • Strapping (Felts)
    A method of installing roofing rolls or sheet good materials parallel with the slope of the roof.
  • Straw Nail
    A long-shanked nail. Sometimes used for fastening over tile at hips and ridges. See Fastener.
  • Stress
    The internal resistance of a material to a force, measured as a force per unit area.
  • Stress Wrinkling
  • Strike-Through
    A term used in the manufacture of fabric-reinforced polymeric sheeting to indicate that two layers of polymer have made bonding contact through the scrim or reinforcement.
  • Strip Shingles
    A single layer of shingle. Asphalt shingles that are manufactured in strips, approximately three times as long as they are wide.
  • Strippable Films
    Added protection of plastic films sometimes applied to coated or finished metals after the coil coating process. Applied after prime and top coats to resist damage to the finish prior to and during shipping, fabrication, and installation.
  • Stripping
    Membrane flashing strips used for sealing metal flashing into roof membrane.
  • Stripping In
    Application of membrane stripping ply or plies.
  • Structural Panel
    A panel designed to be applied over open framing in which a structural deck is not required.
  • Styrene Butadiene
    High molecular weight polymers having rubber-like properties, formed by the random copolymerization of styrene and butadiene monomers.
  • Styrene-Butadiene-Styrene Block Copolymer
    A synthetic rubber based on block copolymers having a rubber center block and two polystyrene end blocks, they combine the properties of a thermoplastic resin with those of butadiene rubber. The hard, glassy styrene blocks provide mechanical strength and improve the abrasion resistance, while(...)
  • Substrate
    Generally used on top of the structural roof deck or insulation then a vapor retarder installed on them. Commonly made of: Gypsum Board, Modified Fiber, Reinforced Gypsum, Plywood, High-density Wood Fiber, Mineral Fiber, Perlite.
  • Sump
    An intentional depression around a roof drain or scupper that serves to promote drainage.
  • Superimposed Loads
    Loads that are added to existing loads. For example, a large stack of insulation boards placed on top of a structural steel deck or stacking of bundles of shingles on ridge of roof.
  • Surface Active Agent
    Used to alter the surface tension of liquids. An ingredient in SPF formulations to aid in mixing and controlling cell size.
  • Surface Erosion
    The wearing a way of a surface due to abrasion, dissolution, or weathering.
  • Surfacing
    The top layer or layers of a roof covering, specified or designed to protect the underlying roofing from direct exposure to the weather.
  • Synthetic Rubber
    Any of several elastic substances resembling natural rubber, prepared by the polymerization of butadiene, isoprene, and other unsaturated hydrocarbons. Synthetic rubber is widely used in the fabrication of single-ply roofing membranes.
  • t

  • T&G
    One of the oldest types of dimensional structural wood used as a roof decking. The sides are cut with a convex and concave groove, so adjacent planks may join in alignment with each other to form a uniform deck.
  • Tab
    The exposed portion of a strip shingle defined by its cutouts.
  • Talc
    Whitish powder applied at the factory to the surface of some roofing materials, used as a release agent to prevent adhesion of the membrane to itself.
  • Tapcon®
    Trade name concrete anchor screw. Available in original blue, white ultra-shield, 410 stainless steel, maxi-set, and heavy duty. See Fasteners.
  • Tapered Edge Strip
    A tapered insulation strip used to elevate and slope the roof at the perimeter and at curbs or provide a gradual transition from one layer of insulation to another.
  • Taping
    The technique of connecting joints between insulation boards or deck panels with tape; or the technique of using self-adhering tape-like materials to seam or splice single-ply membranes.
  • Tar
    A brown or black bituminous material, liquid or semi-solid in consistency, in which the predominating ingredients are bitumen’s obtained as condensates in the processing of coal, petroleum, oil-shale, wood, or other organic materials.
  • Tar Boils
    Bubbles of moisture vapor encased in a thin film of bitumen.
  • Tear-Off
    The removal of all roof system components down to the structural deck.
  • Tear Resistance
    Load required to tear a material, when the stress is concentrated on a small area of the material by the introduction of a prescribed flaw or notch. Expressed in psi (pounds force) per inch width.
  • Tear Strength
    The maximum force required to tear a specimen.
  • Telegraphing
    A shingle distortion that may arise when a new roof is applied over an uneven surface.
  • Tensile Fatigue
    The ability of a given membrane material to resist “fatigue” and/or other damage.
  • Tensile Strength
    The maximum force (longitudinal pulling stress) a material can bear without tearing or breaking apart.
  • Tensile Test
    A test in which a specimen is subjected to increasing longitudinal pulling stress until fracture occurs.
  • Termination
    The method of anchoring and/or sealing the free edges of the membrane in a roofing or waterproofing system.
  • Terne
    An alloy of lead and tin, used to coat sheets of carbon steel or stainless steel for use as metal roofing sheet.
  • Test Cut
    A sample of the roof, which may contain all components or just the membrane, usually used to diagnose the condition of the existing membrane, evaluate the type and number of plies or number of membranes, or rates of application weight. Test Cuts are not limited to membranes.
  • Thermal Barrier
    A material applied over polyurethane foam designed to slow the temperature rise of the foam during a fire and delay its involvement in the fire.
  • Thermal Conductance
    A unit of heat flow that is used for specific thicknesses of material or for materials of combination or composite construction, such as laminated insulation.
  • Thermal Conductivity
    The heat energy that will be transmitted by conduction through 1 square foot of 1-inch thick homogeneous material in one hour when there is a difference of 1-degree Fahrenheit perpendicularly across the two surfaces of the material. The formula for thermal conductivity is: k=Btu/Square(...)
  • Thermal Image
    A visual representation of temperature distribution over a surface area. The image is displayed on a screen, presenting the response to infrared light waves.
  • Thermal Insulation
    A material applied to reduce the flow of heat.
  • Thermal Movement
    Changes in the dimension of a material because of temperature changes.
  • Thermal Resistance
    Index of a material’s resistance to heat flow; it is the reciprocal of thermal conductivity (k) or thermal conductance (C). The formula for thermal resistance is: R= 1 or R = 1 or R= Thickness in inches.
  • Thermal Shock
    The stress-producing phenomenon resulting from sudden temperature changes in a roof membrane when, for example, a cold rain shower follows a brilliant hot sunshine, which may result in sudden cooling or rapid contraction of the membrane.
  • Thermal Stress
    Stress introduced by uniform or non-uniform temperature change in a structure or material that is contained against expansion or contraction.
  • Thermogram
    Visible light record of the display of an infrared camera system via a Polaroid print, 35mm film, video tape, or computer-generated image.
  • Thermography
    A technique for producing heat “pictures” from the radiant energy emitted from stationary or moving objects without in any way influencing the temperatures of the objects under view. The electronic generation and display of a visible image of an infrared spectrum.
  • Thermoplastic
    Materials that soften when heated and harden when cooled. This process can be repeated provided that the material is not heated above the point at which decomposition occurs.
  • Thermoplastic Olefin Membrane
    A blend of polypropylene and ethylene-propylene polymers. Colorant Membrane: flame retardants, UV absorbers, and other proprietary substances which may be blended with the TPO to achieve the desired physical properties. The membrane may or may not be reinforced.
  • Thermoset
    A material that solidifies or “sets” irreversibly when heated. This property is usually associated with cross-linking of the molecules induced by heat or radiation.
  • Thinner
    A liquid used to reduce the viscosity of coatings or mastic. Thinners evaporate during the curing process. Thinners may be used as solvents for cleanup of equipment.
  • Tie-In
  • Tie-Off
    The transitional seal used to terminate a roofing or waterproofing application at the top or bottom of flashings, or by forming a watertight seal with the substrate, membrane or adjacent roofing or waterproofing system.
  • Tile
    A roof material made with clay, concrete, and sometimes slate.
  • Toggle Bolt
    A two-piece assembly consisting of a threaded bolt and an expanding clip that can fit through a drilled hole. The clip can spring outward to provide anchorage from the blind side.
  • Tongue and Groove Planks
    One of the oldest types of dimensional structural wood used as a roof decking. The sides are cut with a convex and concave groove, so adjacent planks may join in alignment with each other to form a uniform deck.
  • TPO
    A blend of polypropylene and ethylene-propylene polymers. Colorant Membrane: flame retardants, UV absorbers, and other proprietary substances which may be blended with the TPO to achieve the desired physical properties. The membrane may or may not be reinforced.
  • Traffic Bearing
    In waterproofing, a membrane formulated to withstand a certain amount of pedestrian wear.
  • Transitions
    When a roof plane ties into another roof plane that has a different pitch or slope.
  • 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.
  • Tree-bark Surface Texture
    A term to describing a course texture where valleys form sharp angles. This surface is unacceptable for proper coating.
  • Tuckpointing
    The process of removing deteriorated mortar from an existing masonry joint and troweling new mortar or other filler into the joint
  • Two-Part System
    A coating of SPF formed by the mixing and (usually) the reaction of two different materials.
  • u

  • U-Value
    Overall thermal conductance. U-value is equal to the inverse of the sum of the R-value in a system (U=1/R total).
  • UL
    An organization that tests, rates and classifies roof assemblies for their resistance to: fire, impact, leakage, corrosion of metal components, and wind uplift.
  • Ultimate Elongation
    The amount a material stretches during tensile testing before it ruptures. Usually expressed as a percentage of the original length.
  • Ultraviolet
    Relating to, producing, or employing ultraviolet radiation.
  • Under Drive
    Term used to describe a fastener not fully flush to shingle surface. Also known as a Nail Pop.
  • Undereave
    Underside area of the overhang at the eave of the roof. See Eave.
  • Underlayment
    An asphalt-saturated or synthetic underlayment sheet material (may be self-adhering) installed between the roof deck and the roof system. Underlayment is primarily used to separate the roof covering from the roof deck, to shed water, and to provide secondary weather protection for the roof(...)
  • Underwriters Laboratories, Inc.
    An organization that tests, rates and classifies roof assemblies for their resistance to: fire, impact, leakage, corrosion of metal components, and wind uplift.
  • United States Environmental Protection Agency
    Government agency whos mission is to help protect human health and the environment.
  • Uplift Wind Load
    Pressures from wind flow that cause lifting effects. See Wind Loads.
  • UV
    Relating to, producing, or employing ultraviolet radiation.
  • v

  • Valley
    The internal angle formed by the intersection of two sloping roof planes to provide water runoff.
  • Valley Flashing
    Typically made from a metal in a preformed “W” style or roll style. Preformed designs are typically used for metal or tile roof coverings. Other materials can consist of impervious material installed to prevent the passage of water into a structure from a joint or as part of a weather(...)
  • Vapor
    A term used to describe moisture laden air.
  • Vapor Migration
    The movement of water vapor from a region of high vapor pressure to a region of lower vapor pressure.
  • Vapor Pressure
    The pressure at any given temperature exerted by a vapor that is in equilibrium with its liquid or solid form.
  • Vapor Retarder
    A material installed to impede or restrict the passage of water vapor through a roof assembly.
  • Vent
    An opening designed to convey air, heat, water vapor or other gas from inside a building or a building component to the atmosphere.
  • Vent Sleeve
    See Collar.
  • Vermiculite
    An aggregate used in lightweight insulating concrete, formed by the heating and consequent expansion of a micaceous material.
  • Viscous
    Resistant to flow under stress they are usually cohesive and have a sticky consistency.
  • VOC
    Organic materials which evaporate at normal temperatures and pressures; organic materials which have vapor pressures greater than 0.1mm Hg at one atmosphere.
  • Volatile
    A term used to describe a substance which passes off easily as a gas or vapor, evaporating quickly.
  • Volatile Organic Compounds
    Organic materials which evaporate at normal temperatures and pressures; organic materials which have vapor pressures greater than 0.1mm Hg at one atmosphere.
  • Vulcanization
    Any of various processes by which natural or synthetic rubber or other polymeric materials may be cured or otherwise treated (exposed to chemicals, heat, or pressure) to render them non-thermoplastic, and which improve their elastic and physical properties.
  • w

  • Warranty
    Written document of roofing materials or labor for specific roof problems.
  • Water Absorption
    The amount of water absorbed by a material after immersion for a prescribed period. May be expressed as a percentage of the original weight of the material.
  • Water Cure
    A method of curing a material, such as concrete, by applying a fine mist of water over the surface to control the rate of moisture evaporation from the material.
  • Water Stop
    A diaphragm used across a joint as a sealant, usually to prevent the passage of water.
  • Waterproof
    The term of a quality of a membrane, membrane material, or other component to prevent water entry.
  • Waterproofing
    Treatment of a surface or structure to prevent the passage of water under hydrostatic pressure.
  • Weather Infiltration
    The negative condition where rain penetrates the roof. The condition is typically wind-driven.
  • Weathering
    Natural exposure to elements that can affect the physical property of the material.
  • Weep Holes
    Small openings whose purpose is to permit drainage of water that accumulates inside a building component.
  • Wicking
    The process of moisture movement by capillary action, as contrasted to movement of water vapor.
  • Wind Loads
    The force on a structure arising from the impact of wind on it.
  • Wind Uplift
    The force caused by the deflection of wind at roof edges, roof peaks or obstructions, causing a drop-in air pressure immediately above the roof surface. This force is then transmitted to the roof surface. Wind Uplift may also occur because of the introduction of air pressure underneath the(...)
  • Wood Shake
    Wood roofing covering material made of cedar, spruce, or treated pine, typically split on one or both sides; except for tapersawn shakes that are sawn on both sides with a semi-textured look with a stronger shadow line than a wood shingle.
  • Wood Shingle
    Roof covering material, thin sawn wood on both side, machine made of cedar, spruce, or treated pine, and tapered on the end. Split wooden shingles are referred to as shag shingles.
  • Woven Valley
    A method of valley construction in which shingles from both sides of the valley extend across the valley and are woven together by overlapping alternate courses as they are applied. The valley flashing is not exposed.
  • z

  • Zinc
    A metal that has application considerations including high expansion-contraction rates and low-temperature restrictions.

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