Aggregate
Stone, slag or river rock that comes in a variety of sizes. Used as ballast and / or UV protection for certain roof systems, BUR, EPDM etc. |
Alligatoring
A characteristic in asphalt which occurs during aging. Exposed asphalt inherently over time loses volatile oils, in conjuction with oxidation caused by UV exposure (solar radiation) creates a pattern of cracks. These cracks resemble alligator hide. |
Apron Flashing
A term used for a flashing located at the juncture of the top of a sloped roof and a vertical wall, chimney or steeper sloped roof. |
Architectural Shingle
A laminated asphalt shingle that provides a dimensional appearance. |
Asphalt
a dark bituminous substance that is found in natural beds and is also obtained as a residue in petroleum refining and that consists chiefly of hydrocarbons. Asphalt is used in many different roofing products, including but not limited to, shingles, underlayments, emulsions etc. |
Asphalt Shingle
A shingle manufactured by coating a reinforcing material (felt or fibrous glass mat) with asphalt and having mineral granules on the side exposed to the weather (see shingle) |
ASTM
American Society for Testing and Materials |
Ballast
Various materials used to protect roof systems from UV rays, or to prevent blow off of systems which are not fully adhered. River rock, brick, pavers etc. |
Back Nailing
Installation of nails in roof felts (to the deck) under the overlaps along with hot mopping to precent slippage during process. |
Base Sheet (Ply)
An asphalt saturated or coated felt, installed as the first layer (ply) with 4" laps in a built up roof (BUR) system. |
Base Flashing
A portion of the flashing attached to or resting on the deck used to direct the flow of water onto the roof covering |
Bitumen
Bitumens are mixtures of hydrocarbons of natural or pyrogeneous origin; or combinations of both, frequently accompanied by their non metallic derivatives, which may be gaseous, liquid, or solid, and which are completely soluble in carbon disulfide. In the roofing industry the word covers both asphalt and coal tar pitch |
Blister / Blistering
An enclosed bubble (under the surface). Can be caused by different reasons, for example, expansion of trapped air and water - vapour or moisture or other gases. Some blisters will expand during rising outside temperatures, this also causes the plies of roofing material to seperate from each other or from the deck. Blueberry blisters are smaller in size and are more common on unprotected roof systems (smooth modified or BUR without coating or aggregate) |
Blocking (aka Racking)
A method of applying shingles in vertical rows from the eave to the ridge, rather than horizontally from rake to opposing rake. This is not a recommended method of installation, some shingle manufacturers will not warranty this. |
BUR / Built Up Roof
Layers, or plies of roofing felt, bonded together with hot bitumen (see bitumen and asphalt), typically finished with a flood coat of hot bitumen and a protective coating or aggregate (rock etc) |
Cant Strip
A bevelled material used at the intersection of a roof deck with vertical structural detail (parapet wall). Used to support roofing membrane used to form a base wall flashing in order to prevent breakage of materal (felts, modified, membrane etc). Made of various materials including bevelled wood, insulation, grout or concrete etc. |
Cap Sheet
A granulated surface bitumen material commonly used as the top ply of a built up roof system (BUR). Use of aggregate for UV protection is not necessary when a cap sheet is installed. |
Cladding
Material used as the exterior wall enclosure of a building
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Class "A"
Refers to the highest of fire- resistant ratings in regards to roofing materials per ASTM E-108. A Class "A" rating indicates the material is able to withstand severe exposure to fire originating from outside the building in which the material is installed and will not support a flame on it's own. |
Closed Cut Valley
A method of valley application in which shingles from one side of the valley extedn across the valley while shingles from the other side are trimmed back either in the middle of the valley or off center. |
Coal Tar
A dark brown to black colored, semi-solid hydrocarbon produced by the distillation of coal. Coal tar pitch is further refined to conform to certain roofing grade specifications;
Coal Tar Pitch:
A coal tar used as the waterproofing agent in dead-level or low-slope built up roof membranes and membrane waterproffing systems, conforming to ASTM Specification D 450 Type I
Coal tar waterproofing pitch:
A coal tar used as the dampproofing or waterproofing agent in below-grade structures, conforming to ASTM Specification D 450 Type II
Coal Tar Bitumen:
A proprietary trade name for TypeIII coal tar used as the dampproofing or waterproofing agent in dead-level or low slope built up roof membranes and mambrane waterproofing systems, conforming to ASTM D 450 Type III
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Cold Roof Assembly
a rof assembly in which the insulation is located below the deck, and not typically in contact with the deck, allowing for ventilation space. The temperature of the roof assembly remains close to the outside air temperature. |
Composition Shingle
An asphalt shingle roof, non specific to the design. (see further shingle definitions) |
Composite board roof insulation
Rigid board insulation generally comprised of perlite or wood fiberboard factory bonded to polyisocyanurate or polystyrene. |
Compounded 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. |
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