ACIL: American Council of Independent Laboratories
Acrylic Coating: A coating system with an acrylic resin base.
Acrylic Resin: Polymers of acrylic or methacrylic monomers often used as a latex base for coating systems.
Active: Will corrode in the presence of moisture or a "noble" metal.
Adhere: The clinging of one surface to another; either molecularly or otherwise.
Adhesion: The state of adhering
AFA: American Fiberboard Association
AGC: Associated General Contractors of America
Aggregate: A surfacing or ballast for a roof system. Aggregate can be rock, stone, crushed stone or slag, water-worn gravel, crushed lava rock or marble chips.
AHA: American Hardboard Association
AIA: American Institute of Architects
Air Blown Asphalt: Asphalt produced by blowing air through molten asphalt held at an elevated temperature. This procedure is used to modify properties of the asphalt.
Alligatoring: The cracking of the surfacing bitumen on a built-up roof, producing a pattern of cracks that resemble an alligators hide. <picture>
Aluminized Steel: Sheet steel with a thin aluminum coating on the surface to enhance the steels ability to withstand weathering.
Aluminum: A non-rusting metal used in roofing for metal roofing and the fabrication of gutter and flashings.
Ambient Temperature: The temperature of the air.
Anodic: When two metals are connected in an electrolyte, they will form a galvanic cell, with the higher metal in the galvanic series being the anode. The anodic will oxidize and produce an electrical current which protects the cathode from corrosion.
ANSI: American National Standards Institute
APA: American Plywood Association
APP: See Atactic Polypropylene.
Application Rate: The rate at which a material is applied per unit area.
Apron Flashing: A flashing located at the low end of a curb or penetration.
Architectural Panel: A metal roof panel that usually requires solid decking underneath.
Architectural Shingle: Shingle that provides a dimensional appearance. See also Dimensional Shingle.
Area Divider: A flashed assembly usually extending above the surface of the roof that is anchored to the roof deck. It is used to relieve thermal stresses in a roof system where an expansion joint is not required, or to separate large roof areas.
ARMA: Asphalt Roofing Manufacturers Association
ASA: American Subcontractors Association
Asbestos: An incombustible fibrous mineral form of magnesium silicate formerly used for fireproofing and sometimes used for the reinforcement of roofing materials.
ASC: Associated Specialty Contractors
ASHI: American Society of Home Inspectors
ASHRAE: American Society of Heating, Refrigerating & Air-Conditioning Engineers, Inc.
Asphalt: A substance left as a residue after evaporating or otherwise processing crude oil or petroleum. Asphalt can be refined to conform to various roofing grade specifications:
Asphalt Emulsion: A mixture of asphalt particles and an emulsifying agent such as bentonite clay and water.
Asphalt Felt: An asphalt-saturated and/or an asphalt-coated felt membrane. (See also Felt.)
Asphalt Primer: See Primer.
Asphalt Roof Cement: The proper name for Plastic Cement and Flashing Cement. Asphalt roof cement consists of solvent-based bitumen, mineral stabilizers, and other fibers (sometimes asbestos). Asphalt roof cement is categorized by ASTM standard D 2822-91 (1997) or for non-asbestos, ASTM standard D 4586-93.
ASTM: American Society for Testing and Materials
Atactic Polypropylene: A group of high molecular weight polymers formed by the polymerization of propylene.
Attic: The open area above the ceiling and under the roof deck of a steep-sloped roof.
AWPA: American Wood Preservatives Association
AWS: American Welding Society