the ability to resist being worn away by contact with another moving, abrasive surface, such as foot traffic, mechanical equipment, wind-blown particles, etc.
A
Absorption
The ability of a material to accept within its body, quantities of gases or liquid, such as moisture
Accelerated weathering
The exposure of a specimen to a specified test environment for a specified time with the intent of producing in a shorter time period, effects similar to actual weathering.
Acid Etch
In waterproofing, the use of a strong acid to remove the surface of concrete to expose the aggregate.
Acrylic Coating
A liquid coating system based on an acrylic resin. Generally, a latex-based coating system that cures by air drying.
Acrylic Resin
Polymers of acrylic or methacrylic monomers. Often used as a latex base for coating systems.
Adhesion
A steady or firm attachment.
Adhesive Bond Break
A material to facilitate independent movement between two units that would otherwise bond together.
Aged R-value
Thermal resistance value established by utilizing artificial conditioning procedures for a prescribed time period.
Aggregate
(1) crushed stone, crushed slag or water-worn gravel used for surfacing a built-up roof system; (2) any granular material.
Air Leakage
The unintended movement of air from a location where it is intended to be contained to another location
Air-Blown Asphalt
Asphalt produced by blowing air through molten asphalt to raise its softening point and modify other properties.
Alligatoring
The cracking of the surfacing bitumen on a bituminous roof or coating on a SPF roof, producing a pattern of cracks similar to an alligator’s hide; the cracks may not extend completely through the surfacing bitumen or coating.
Anodic
A metal or material that readily gives up electrons to a cathodic (noble) material. An anodic material will corrode in the presence of moisture when in contact with a cathodic metal. Anodic materials are usually replaceable, and sacrifice themselves in order to preserve the cathodic material.
ANSI
American National Standards Institute
Anticapillary Hem
A hem used in a metal panel seam to reduce the potential for water migration
APA
American Plywood Association
APC
American Plastics Council
APP
see Atactic polypropylene
Application Rate
The average 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 a sloped roof and a vertical wall, chimney or steeper-sloped roof
Architectural Panel
A metal roof panel, typically a double standing seam or batten seam; usually requires solid decking underneath and relies on slope to shed water.
Architectural Shingle
An asphalt shingle that provides a dimensional appearance.
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 accommodate thermal stresses in a roof system where an expansion joint is not required, or to separate large roof areas or separate roof systems comprised of different/incompatible materials, and may be used to facilitate installation of tapered insulation.
Area Practices
Design or application techniques peculiar to a specific geographical region
ARMA
Asphalt Roofing Manufacturers Association
Asbestos
A group of natural, fibrous, impure silicate materials.
ASHRAE
American Society of Heating, Refrigerating and Air-Conditioning Engineers
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. Asphalt may be further refined to conform to various roofing grade specifications:
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Dead-level asphalt
a roofing asphalt conforming to the requirements of ASTM Specification D 312, Type I. -
Flat asphalt
a roofing asphalt conforming to the requirements of ASTM Specification D 312, Type II. -
Steep asphalt
a roofing asphalt conforming to the requirements of ASTM Specification D 312, Type III. -
Special steep asphalt
a roofing asphalt conforming to the requirements of ASTM Specification D 312, Type IV.
Asphalt Emulsion
A mixture of asphalt particles and emulsifying agent, such as bentonite clay and water.
Asphalt Felt
An asphalt-saturated and/or asphalt-coated felt (see Felt).
Asphalt Primer
See Primer
Asphalt Roof Cement
A trowelable mixture of solvent-based bitumen, mineral stabilizers, other fibers and/or fillers. Classified by ASTM Standard D 2822-1 Asphalt Roof Cement, and D 4586-2 Asphalt Roof Cement, Asbestos-Free, Types I and II. Type I is sometimes referred to as “plastic cement,” and is made from asphalt characterized as self-sealing, adhesive and ductile, and conforming to ASTM Specification D 312, Type I; Specification D 449, Types I or II; or Specification D 946. Type II is generally referred to as “vertical-grade flashing cement,” and is made from asphalt characterized by a high softening point and relatively low ductility, and conforming to the requirement of ASTM Specification D 312, Types II or III; or Specification D 449, Type III.
See Plastic cement and Flashing cement.
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)
Asphaltine
A high molecular weight hydrocarbon fraction precipitated from asphalt by a designated solvent (paraffinic naphtha) at a specified temperature and solvent-asphalt ratio
ASTM
American Society for Testing and Materials
Atactic Polypropylene
A group of high molecular weight polymers formed by the polymerization of propylene.
Attic
The cavity or open space above the ceiling and immediately under the roof deck of a steep-sloped roof.