Glossary: A to C
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.
Alligatoring: The cracking of the surfacing bitumen on a built-up roof, producing a pattern of cracks that resemble an alligator's hide
Aluminum: A non-rusting metal used in roofing for metal roofing and the fabrication of gutter and flashings.
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
Asphalt Felt: An asphalt-saturated and/or an asphalt-coated felt membrane.
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.
Ballast: A material installed over the top of a roof membrane to help hold it in place. Ballasts are loose laid and can consist of aggregate, or concrete pavers.
Barrel Roof: A roof configuration with a partial cylindrical shape to it.
Base Flashing (membrane base flashing): Plies of roof membrane material used to seal a roof at the vertical plane intersections, such as at a roof-wall and roof-curb junctures.
Base Ply: The primary ply of roofing material in a roof system.
Base Sheet: An asphalt-impregnated, or coated felt used as the first ply in some built-up and modified bitumen roof systems.
Batten: A strip of wood usually fastened to the structural deck for use in attaching a primary roof system such as tile.
Bay Window: A combination of three window units joined together that project outwards. The center unit is parallel to the wall and the two units each side are usually 45° or 90° (right angles) to the wall but can be any angle.
Bermuda Style roof: A metal roof that has a step profile.
Birdstop: Barrier placed under the lower course of round spanish type tile, to keep birds from making nests in the roof.
Bitumen: Any of various flammable mixtures of hydrocarbons and other substances, occurring naturally or obtained by distillation from coal or petroleum, that are a component of asphalt and tar and are used for surfacing roads and for waterproofing.
Blind-Nailing: The use of nails so that they are not exposed to the weather in the finished roofing system.
Blister: A pocket of air trapped between layers of felt or membrane. Blisters are usually caused by water or other foreign substances.
Bonding Agent: A chemical agent used to create a bond between two layers.
Boot: A piece of material preformed to protect roof penetrations from dirt, moisture and other foreign and/or damaging substances.
Buckle: A long, tented displacement of a roof membrane. Can occur over insulation and deck joints.
Built-in Gutter: A rain gutter built into the roof eave and supported by the roof structure.
Built-up Roof: A low-slope (or flat-seeming) roof covered with alternating layers of roofing felt and hot-mapped asphalt and topped off with a layer of gravel.
Built-up Roof Membrane: A roof membrane consisting of layers of bitumen, which serves as the waterproofing component, with plies of reinforcement fabric installed between each layer. The reinforcement material can consist of bitumen-saturated felt, coated felt, polyester felt or other fabrics. A surfacing is generally applied and can be asphalt, aggregate, emulsion or a granule-surfaced cap sheet.
BUR: An acronym for Built-Up Roof. See Built-Up Roof.
Butyl Rubber: A butyl-based, synthetic elastomer.
Butyl Tape: A sealant tape used in numerous sealant applications such as sealing sheet metal joints.
Canopy: An overhang, usually over entrances or driveways.
Cant Strip: A triangular-shaped strip of material used to ease the transition from a horizontal plane to a vertical plane. Cant strips can be made of wood, wood fiber, perlite, or other materials.
Cap Flashing: A material used to cover the top edge of base flashings or other flashings.
Cap Sheet: A granule-surfaced membrane often used as the top ply of BUR or modified roof systems.
Castellated: Decorated with battlements (a parapet with alternating indentations and raised portions); also called crenellation. Buildings with battlements are usually brick or stone.
Chalk Line: (1) A string on a reel in a container that can hold chalk; (2) A line made on by pulling taut a string coated with chalk and snapping it.
Channel Flashing: Flashing with a built-in channel for runoff; used where roof planes intersect other vertical planes.
Chimney Cricket: Roof boarding and flashing used to create a pitched surface behind a chimney to deflect running water away from the back of the chimney.
Cladding: A material used to cover the exterior wall of a building.
Cleat: A continuous metal strip used to secure two or more metal roof components together. Commonly used along with coping or gravel stop on tall buildings.
Clerestory (Clearstory): A room that extends above an abutting roof section of a building.
Clip: A small cleat.
Clipped Gable: A gable cut back at the ridge in a small hip configuration.
Closed-Cut Valley: A method of valley application in which shingles from one side of the valley extend across the valley while shingles from the other side are installed over the top of those and then trimmed back approximately 2 inches from the valley centerline.
Coal Tar Pitch: A type of coal tar used in dead-level or low-slope built-up roofs. It is not for use in roofs exceeding ?" in 12" (2%) slope.
Cold Process Built-Up Roof: A roof consisting of multiple plies of roof felts laminated together with adhesives that usually come right out of a can or barrel and require no heating.
Conductor Box: An enlargement or catch basin at the top of a downspout or leader to receive rainwater from a gutter or scupper. (Also called conductor, leader head, leader box, collector, collector head, collector box, scupper head, catch basin, or bell.)
Conductor Head: A component used to direct water from a through-wall scupper to a downspout.
Combing Ridge: A term used to describe an installation of finishing slate at the ridge of a roof whereby the slates on one side project beyond to the apex of the ridge.
Composition Shingle: A type of shingle used in steep-slope roofing and generally comprised of weathering-grade asphalt, a fiber glass reinforcing mat, an adhesive strip, and mineral granules.
Condensation: The conversion of water vapor to liquid state when warm air comes in contact with a cold surface. (See also href="/cmsrf/glossary-d-i.htm">Dew Point.)
Contact Cements: Adhesives used to adhere or bond roofing components.
Coping: The piece of material used to cover the top of a wall and protect it from the elements. It can be constructed from metal, masonry, or stone.
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 turns a greenish color after being exposed to the weather for a length of time and appears in the middle of the Galvanic Series.
Copper Patina Solution: Chemical ingredients and solutions to pre-patina new copper.
Cornice: The portion of the roof projecting out from the side walls of the house.
Counter Batten: Wood strips installed vertically on sloped roofs over which horizontal battens are secured.
Counterflashing: The flashing which is imbedded at its top in a wall or other vertical structure and is lapped down over shingle flashing.
Courses: Horizontal rows of shingles or tiles.
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 90? angle.
Creep: Movement of roof membrane causing the roof system to be deformed.
Cricket: A roof component used to divert water away from curbs, platforms, chimneys, walls, or other roof penetrations and projections.
Crocket: Decorative ornament usually on a spire or cupola.
Cross Ventilation: The effect of air moving through a roof cavity between vents.
Cupola: A relatively small roofed structure set on the ridge of a main roof area. Also known as a Crow's Nest.
Curb: (1) A raised member used to support skylights, HVAC units, exhaust fans, hatches or other pieces of mechanical equipment above the level of the roof surface, should be a minimum of eight inches (8") in height; (2) A raised roof perimeter that is relatively low in height.
Cure: A process by which a material is forms permanent molecular linkages by exposure to chemicals, heat, pressure, and/or weathering.
Cutback: Bitumen thinned by solvents that is used in cold-process roofing adhesives, roof cements, and roof coatings.
Cutout: The open area between shingle tabs. Also known as a "throat".