Glossary

3-tab shingle is a type of asphalt roofing material featuring a flat, rectangular design with three evenly spaced cutouts along the lower edge, creating the appearance of three separate shingles per strip.

A-frame is a roof structure characterized by steeply angled sides that meet at the top in the shape of the letter "A," forming a triangular silhouette that extends to the building’s foundation.

Abrasion resistance is a material property that measures a roofing surface’s ability to withstand wear, scraping, or erosion caused by mechanical action, such as foot traffic, wind-blown debris, or equipment movement.

Absorption is a process in roofing where a material takes in and retains moisture or liquid, typically measured as the percentage increase in weight after exposure to water under controlled conditions.

Accelerated weathering is a laboratory testing process that simulates the long-term effects of environmental conditions such as sunlight, moisture, and temperature on roofing materials to evaluate their durability and performance.

Acrylic resin is a synthetic polymer material used in roofing systems as a base for coatings and sealants, providing a durable, flexible, and UV-resistant protective layer on various roof surfaces.

Adhesion is the molecular attraction that causes roofing materials, such as membranes or coatings, to bond and remain attached to substrates or other surfaces within a roofing system.

Adhesive is a bonding agent used in roofing systems to securely attach membranes, insulation, or other materials to substrates, ensuring structural integrity and weather resistance without mechanical fasteners.

ADR Institute of Canada is a national organization that sets standards and provides accreditation for alternative dispute resolution professionals, including those involved in construction and roofing industry conflicts.

Aged R-value is a measurement of the long-term thermal resistance of roofing insulation, representing its insulating effectiveness after exposure to real-world aging factors such as heat, moisture, and time.

Aging is a process in which roofing materials deteriorate over time due to exposure to environmental factors such as sunlight, moisture, temperature fluctuations, and pollutants, leading to changes in physical and chemical properties.

Air barrier is a continuous system of materials and assemblies installed in a roof or building envelope to control the movement of air into and out of the structure.

Albedo is a measure of a roofing material’s ability to reflect solar radiation from its surface, expressed as a ratio from 0 (no reflection) to 1 (total reflection).

Alberta Allied Roofing Association (AARA) is a professional trade organization in Alberta that represents, regulates, and supports roofing contractors, suppliers, and industry stakeholders to uphold standards in roofing construction and practices.

Alberta Children’s Hospital Foundation is not a roofing term; it is a charitable organization supporting the Alberta Children’s Hospital, and does not refer to any roof shape, structure, or construction element.

Alberta Roofing Contractors Association (ARCA) is a professional trade organization in Alberta, Canada that sets technical standards, specifications, and guidelines for roofing contractors and roofing system installations.

Algae discoloration is a staining or dark streaking on roofing surfaces caused by the growth of airborne algae, typically Gloeocapsa magma, which thrives in moist environments and feeds on roofing materials.

Alligatoring is a roofing condition where the surface of asphalt-based materials develops a pattern of cracking that resembles alligator skin, caused by aging, UV exposure, and loss of flexibility in the material.

Aluminum is a lightweight, corrosion-resistant metal used in roofing systems as panels, shingles, or flashing to provide durable, weatherproof coverage and structural protection for buildings.

Aluminum Association (AA) is a standards organization that establishes specifications and designations for aluminum materials used in roofing and construction, ensuring uniformity in alloy composition, mechanical properties, and product identification.

American Arbitration Association (AAA) is a nonprofit organization that administers arbitration and mediation services for resolving construction and roofing contract disputes outside of court.

American Institute of Architects (AIA) is a professional organization for architects in the United States that establishes industry standards, including contract documents and guidelines, for architectural design and construction practices.

American Institute of Steel Construction (AISC) is a technical organization that develops standards, specifications, and guidelines for the design, fabrication, and erection of structural steel used in building and roofing systems.

American National Standards Institute (ANSI) is a private, non-profit organization that oversees the development and accreditation of consensus standards for products, services, processes, and systems in the roofing and construction industries.

American Policyholder Association (APA) is a nonprofit organization that advocates for insurance policyholders’ rights, investigates insurance fraud, and promotes ethical practices within the property insurance and roofing industries.

American Rainwater Catchment Systems Association (ARCSA) is a professional organization that establishes standards, guidelines, and educational resources for the design, installation, and maintenance of rainwater harvesting systems in the United States.

American Society for Testing and Materials (ASTM) is a globally recognized organization that develops and publishes technical standards for materials, products, systems, and services used in construction, including roofing systems.

Angi is an online platform that connects homeowners with local roofing contractors and service professionals for repair, installation, and maintenance projects.

Apron Flashing is a flat or angled strip of metal installed at the intersection where a roof meets a vertical surface, such as a wall or chimney, to direct water away from the joint.

Architectural Shingles is a type of asphalt roofing material composed of multiple laminated layers, designed to create a dimensional, contoured appearance that mimics the look of traditional wood or slate shingles.

ASHRAE is a professional organization that develops standards and guidelines for heating, ventilation, air conditioning, refrigeration, and building energy efficiency, including those affecting roofing system design and performance.

Asian traditional style is a roofing design characterized by curved, upturned eaves and layered, overlapping tiles, typically constructed with timber framing to create distinctive, ornate silhouettes found in East and Southeast Asian architecture.

Asphalt is a black, sticky, semi-solid form of petroleum used as a waterproofing and binding agent in roofing systems, typically applied as shingles or built-up roofing membranes.

Asphalt Institute is a professional organization that develops technical standards, research, and educational resources for the design, production, and application of asphalt materials in roofing and pavement construction.

Asphalt Primer is a liquid bituminous coating applied to prepared surfaces such as concrete, metal, or wood to promote adhesion of asphalt-based roofing materials and ensure proper bonding during roof system installation.

Asphalt roof cement is a thick, bituminous compound used to seal, bond, and waterproof joints, flashings, and repairs on asphalt-based roofing systems.

Asphalt Roofing Manufacturers Association (ARMA) is a trade organization representing North American manufacturers of asphalt roofing products, providing technical standards, industry guidelines, and educational resources for asphalt-based roofing systems.

Asphalt Shingles is a type of overlapping, rectangular roofing material composed of a fiberglass or organic mat coated with asphalt and mineral granules, designed to form a watertight, weather-resistant roof covering.

Atlantic Provinces Roofing Contractors Association (APRCA) is a regional trade organization representing roofing contractors and industry stakeholders in Canada’s Atlantic provinces, focused on standards, education, and advocacy within the roofing sector.

Attic is a space or room located directly below the pitched roof of a building, enclosed by the roof structure and exterior walls, often used for storage or housing mechanical systems.

Attic vent is a roof or gable-mounted opening or device designed to allow air to flow into or out of an attic space, facilitating passive ventilation of the building envelope.

Authority Having Jurisdiction (AHJ) is the official organization, office, or individual responsible for enforcing building codes, standards, and regulations on roofing projects within a specific geographic area or project scope.

Back surfacing is a layer of fine mineral material applied to the underside of asphalt roofing shingles or rolls to prevent sticking during storage and handling.

Baeumler Approved is a certification program that verifies contractors and home service companies meet specific professional, safety, and quality standards established by the Baeumler Approved organization.

Ballast is a layer of heavy material, such as gravel or concrete pavers, placed on flat or low-slope roofing membranes to hold them in place and protect against wind uplift.

Barge board is a board or trim fixed to the projecting gable end of a pitched roof, covering and protecting the roof timbers and providing a finished edge along the roofline.

Barrel roof is a curved roofing structure with a semi-cylindrical shape resembling a barrel cut lengthwise, typically spanning large spaces without internal supports and often constructed from materials like metal, concrete, or wood.

Base flashing is a strip of waterproof material installed at the joint where a roof surface meets a vertical wall or projection, directing water away from the intersection to prevent leaks.

Base sheet is a foundational layer of roofing material, typically made of asphalt-impregnated felt or fiberglass, installed directly over the roof deck to provide a substrate for additional membrane layers in built-up or modified bitumen roofing systems.

Base-ply sheet is a foundational layer of roofing membrane, typically made from asphalt-saturated or modified bitumen material, installed directly over the roof deck to provide structural support in multi-ply roof systems.

Batten is a thin, narrow strip of wood, metal, or plastic installed horizontally or vertically on a roof structure to provide a fixing point for roofing materials such as tiles, slates, or shingles.

BC Children’s Hospital Foundation is a charitable organization that raises funds to support the infrastructure, research, and patient care initiatives of BC Children’s Hospital, rather than a roofing system or construction term.

BIPV is a roofing system where photovoltaic materials are integrated directly into the building envelope, such as roof tiles or shingles, to serve as both a weather barrier and a source of solar power.

Bird stop is a metal or plastic barrier installed at the eaves or ridges of tile roofs to block gaps and prevent birds or debris from entering beneath the roofing tiles.

Bitumen roofing is a flat or low-slope roofing system composed of layers of asphalt-based bitumen, reinforced with materials like fiberglass or polyester, and applied as built-up roofing (BUR) or modified bitumen membranes.

Blackberry is a small, raised blister or bubble that forms on a built-up roofing membrane due to trapped moisture or air beneath the surface layers.

Blisters is a roofing defect characterized by raised bubbles or pockets formed between roof membrane layers or between the membrane and substrate, caused by trapped air, moisture, or improper adhesion.

Blow-Off Resistance is a measure of a roofing system’s ability to withstand uplift forces from wind without components or materials being detached or displaced from the roof structure.

Blow-Offs is a roofing term referring to sections of roofing material, such as shingles or membranes, that are forcibly detached and removed from the roof structure by strong winds or severe weather conditions.

Bonnet roof is a dual-pitched roof design featuring two slopes on each side, with the lower slope set at a gentler angle and extending outward beyond the walls to form overhanging eaves.

Boot is a pre-formed, waterproof flashing component designed to seal around roof penetrations such as vent pipes, preventing water intrusion at the point where the pipe passes through the roofing material.

Boston Children’s Hospital is a medical facility in Boston, Massachusetts, and not a roofing system or architectural roof type.

Brake is a mechanical tool used in roofing and sheet metal work to bend, fold, or shape metal panels and flashings to precise angles and dimensions.

Bridging is a structural technique in roofing where short, horizontal braces are installed between rafters or joists to maintain spacing, distribute loads, and enhance overall stability of the roof framework.

British Columbia Home Builders Association (BCHBA) is a professional organization representing residential construction and renovation companies in British Columbia, setting industry standards and providing education, advocacy, and resources for builders.

British Columbia Roofing Contractors Association (BCRCA) is a professional trade organization representing roofing contractors, suppliers, and consultants in British Columbia, setting industry standards and promoting best practices in roofing construction.

Buckling is a structural deformation in roofing materials where the surface bends or warps out of plane, typically due to moisture, thermal movement, or improper installation, compromising the roof’s integrity.

Building Code is a set of legally enforced regulations that specify minimum standards for the design, construction, alteration, and maintenance of buildings, including roofing systems, to ensure safety and structural integrity.

Building Owners and Managers Association (BOMA) is a professional organization that develops standards for measuring building areas, including roof geometry and structure, to guide property management, leasing, and construction practices.

Built-up roofing (BUR) is a flat or low-slope roofing system composed of multiple alternating layers of bitumen and reinforcing fabrics, finished with a protective surfacing such as gravel or mineral cap sheets.

Bundle is a packaged unit of roofing materials, such as shingles or shakes, that is wrapped and bound together for transport and installation, typically containing a specific quantity to cover a defined roof area.

Butt edge is the lower, exposed edge of a roofing shingle that is visible once installed and forms the bottom line of each shingle course on a roof.

Butt Joint is a connection where two roofing materials or components are placed end-to-end or edge-to-edge without overlapping, forming a straight seam at their adjoining surfaces.

Butterfly roof is a V-shaped roof structure formed by two roof surfaces sloping inward toward a central valley, creating an inverted gable that resembles the wings of a butterfly.

Button Punch is a mechanical process in standing seam metal roofing where a tool crimps or indents overlapping panel seams to securely interlock them without additional fasteners.

California Building Climate Zone is a geographic classification system used in California’s building codes to designate regions with similar climate conditions, guiding energy efficiency and construction requirements for roofing and other building systems.

Camber is a slight upward curve or arch built into a roof, beam, or structural member to counteract anticipated deflection and ensure proper load distribution.

Canadian Arbitration Association (CAA) is a national organization that administers arbitration and mediation services for resolving construction and roofing industry disputes in Canada, providing structured procedures outside of court litigation.

Canadian Condominium Institute (CCI) is a national, independent, nonprofit organization in Canada that provides education, resources, and advocacy for condominium owners, boards, and professionals involved in condominium management and governance.

Canadian Construction Materials Centre (CCMC) is a national evaluation service in Canada that assesses and certifies construction materials, products, and systems for compliance with building codes and technical standards.

Canadian Home Builders' Association (CHBA) is a national organization representing residential construction professionals in Canada, setting standards and providing guidance on building practices, codes, and industry regulations.

Canadian Roofing Contractors Association (CRCA) is a national trade organization in Canada representing roofing and related sheet metal contractors, establishing industry standards, technical guidelines, and best practices for roofing construction and maintenance.

Canadian Sheet Metal and Roofing Contractors Association (CSMRCA) is a national trade organization in Canada representing contractors involved in the installation, fabrication, and maintenance of sheet metal and roofing systems.

Canopy is a projecting roof structure, typically attached to a building’s exterior, designed to provide shelter or shade over entrances, walkways, or loading areas without enclosing the space beneath.

Cant is a beveled or angled strip of material installed at the junction of a flat roof and a vertical surface to create a smooth transition and reduce sharp angles.

Cap Flashing is a protective metal covering installed over the top edge of base flashing or masonry walls to prevent water infiltration at roof and wall intersections.

Cap sheet is a flexible, reinforced membrane layer installed as the top surface of a multi-ply low-slope or flat roofing system, typically composed of bitumen and embedded mineral granules for weather protection.

Capillary Action is a physical phenomenon where water moves upward or laterally through narrow gaps or porous materials in roofing systems due to adhesive and cohesive forces, potentially leading to unintended moisture intrusion.

Caulking is a flexible sealing material applied to joints, seams, or gaps in roofing systems to prevent water, air, and debris infiltration by creating a weather-resistant barrier.

Cavity wall is a type of wall construction consisting of two parallel masonry walls separated by an air space or cavity, designed to improve insulation and prevent moisture penetration in buildings.

Chalk is a fine, powdery substance used in roofing to mark straight lines or reference points on surfaces, typically applied with a chalk line tool for accurate layout and alignment during installation.

Chalk line is a construction tool consisting of a string coated with chalk powder, used to mark straight, temporary reference lines on roofing surfaces for accurate alignment and layout during installation.

Chalking is a powdery residue that forms on the surface of roofing materials, such as coatings or membranes, due to the degradation of binders from prolonged exposure to ultraviolet (UV) radiation and weathering.

Children’s Hospital of Eastern Ontario is a medical facility in Ottawa, Canada, featuring a flat roof structure with integrated mechanical penthouses and rooftop equipment, designed to support complex healthcare operations and infrastructure.

Chimney is a vertical masonry or metal structure that extends above the roofline to safely vent smoke, gases, and combustion byproducts from fireplaces, stoves, or furnaces to the outside atmosphere.

Chimney collar is a sheet metal flashing installed around the base of a chimney where it penetrates the roof, forming a waterproof seal between the chimney and roofing materials to prevent water intrusion.

Cladding is a protective external layer or covering applied to a building’s roof or walls to shield the underlying structure from weather and environmental elements.

Class 4 impact resistance is a roofing material rating indicating the highest level of durability against hail and debris impact, as tested under UL 2218 standards for structural integrity and surface protection.

Class A Fire Resistance is a roofing classification indicating the highest level of fire protection, where the roof assembly can withstand severe fire exposure and resist flame spread according to standardized testing protocols.

Class B fire resistance is a roofing classification indicating that the roof assembly can withstand moderate fire exposure and resist the spread of flames, as tested under standardized laboratory conditions.