Calender: A machine used to laminate sheeting or for applying coating with a specified thickness and/or surface attribute.
Calendering: A specific process used to manufacture some membranes such as PVC.
Camber: A slight convex curve of a surface.
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. (See also "Coping")
Cap Sheet: A granule-surfaced membrane often used as the top ply of BUR or modified roof systems.
Capacitance Meter: A device for locating moisture entrapped within a roof assembly by measuring the ratio of change to the potential difference between two conducting elements that are separated by a non-conductor.
Capillarity: The action by which the surface of a liquid (where it is in contact with a solid) is elevated or depressed, depending upon the relative attraction of the molecules of the liquid for each other and for those of the solid.
Catalyst: A substance that effects a chemical reaction and/or the rate at which a chemical reaction takes place. In roofing, catalysts are used in SPF roofing.
Caulking: A composition of vehicle and pigment, used at ambient temperatures for filling joints, that remains elastic for an extended period after application.
C-Channel: A structural framing member that, when viewed cross-sectionally, has the shape of a "C".
CERL: Construction Engineering Research Laboratory
Chemical Resistance: A materials ability to retain its properties when it comes into contact with certain chemicals.
CPE (Chlorinated Polyethylene): A flexible elastomeric material used in the manufacture of some single ply roof membranes.
CSPE (Chlorosulfonated Polyethylene): A synthetic, rubber-like thermoset material, based on high molecular weight polyethylene with suphonyl chloride, usually formulated to produce a self-vulcanizing membrane. Chlorosulfonated Polyethylene or CSPE. Best know as Hypalon™, it was developed in 1951 by DuPont.
Cladding: A material used to cover the exterior wall of a building.
Cleat: A continuous metal strip (usually concealed) used to secure metal roof components. Commonly used to secure coping or gravel stop.
Clerestory: A room that extends above an abutting roof section of a building.
Clip: A small cleat.
Closed-Cut Valley: A method of valley application in fiberglass or asphalt shingle roof installations 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 (cut) approximately 2 inches from the valley centerline.
Closure Strip: A material used to close openings created by joining metal panels or sheets and flashings.
Coal Tar Bitumen: A proprietary trade name for Type III coal tar used in dead-level or low-slope built-up roofs. It is not for use in roofs exceeding ¼" in 12" (2%) slope.
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 ¼" in 12" (2%) slope.
Coal Tar Felt: A roofing membrane saturated with refined coal tar.
Coal Tar Roof Cement: A trowelable mixture of processed coal tar base, solvents, mineral fillers and/or fibers.
Coated Base Sheet: An asphalt-saturated base sheet membrane later coated with harder, more viscous asphalt, thereby increasing its impermeability to moisture.
Coated Felt: An asphalt-saturated ply sheet that has also been coated on both sides with harder, more viscous asphalt.
Coating: A layer of material that is spray, roller, or brush applied over a surface for protection or sometimes decoration.
Cohesion: Mutual attraction by which the elements or particles of a body or substance are held together.
Cold Forming: The process of shaping metal into desired configurations at ambient room temperature.
Cold Process Built-Up Roof: A roof membrane constructed of multiple plies of roofing felt adhered in alternate applications of adhesives that usually come right out of a can or barrel and require no heating.
Collector Head: A component used to direct water from a through-wall scupper or a gutter to a downspout. Also known as a Conductor Head.
Column: A vertical structural member placed on a footing or foundation used to support horizontal above-ground building components.
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.
Combustible: Capable of igniting and burning.
Composition Shingle: A type of shingle used in steep-slope roofing and generally comprised of weathering-grade asphalt, a fiberglass or organic fiber reinforcing mat, an adhesive strip, and mineral granules.
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. Some of the membranes listed in this generic category are CPA, EIP, NBP, and TPA.
Concealed-Nail Method: A method of installing asphalt roll roofing material in which all nails or fasteners are driven into the underlying roofing and covered by an overlapping course.
Condensate: The liquid resulting from condensation.
Condensation: The conversion of water vapor to liquid state when warm air comes in contact with a cold surface.
Conduction: The transmission or conveying of something through a medium or passage, especially the transmission of electric charge or heat through a conducting medium without perceptible motion of the medium itself.
Conductor Head: A component used to direct water from a through-wall scupper or a gutter to a downspout. Also known as a Collector Head.
Coping: the piece of material used to cover the top of a wall and protect it from the elements. Copings are typically constructed from metal or, masonry.
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.
Cornice: A horizontal projecting part that crowns the wall of a building.
Counter Batten: Wood strips installed vertically on sloped roofs over which horizontal battens are secured.
Counterflashing: Formed metal sheeting secured to (or protruding from) walls, curbs, or other surfaces, for use in protecting the top edge of base flashings from exposure to weather.
Course: (1) The term used for each row of roofing material that forms the roofing or flashing system; (2) One of multiple layers materials applied to a surface. For example, a three-course flashing consists of a layer of mesh or other reinforcing material sandwiched between two layers roofing cement.
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. See also Fillet.
Cover Plate: A metal strip sometimes installed over the joint between formed metal pieces.
Coverage: The surface area covered by a material.
Crack: A separation or fracture occurring in a material. See also "Split"
Creep: Movement of roof membrane causing the roof system to be deformed
Cricket: A roof component used to divert water around curbs, platforms, chimneys, walls, or other roof penetrations and projections. See also Saddle.
Cross Ventilation: The effect of air moving through a roof cavity between vents.
CRREL: Cold Regions Research and Engineering Laboratory
CSI: Construction Specifications Institute
CSPE: Chlorosulfonated polyethylene.
Cupola: A relatively small roofed structure set on the ridge of a main roof area. Also known as a Crows 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 forms a permanent molecular linkage by exposure to chemicals, heat, pressure, and/or weathering.
Cure Time: The time necessary for curing to occur.
Curing Agent: A material additive that alters chemical activity between the components resulting in a change in the rate of cure.
Curing Compound: A liquid that is applied to newly installed concrete which slows water loss while curing.
Cutback: Bitumen thinned by solvents that is used in cold-process roofing adhesives, roof cements, and roof coatings.
Cutoff: A detail designed to seal and prevent lateral water movement in the insulation system where the membrane terminates at the end of a days work, or used to isolate sections of the roofing system. It is usually removed before the continuation of the work.
Cutout: The open area between shingle tabs. Also known as a "throat".
BACK TO TOP