Glossary of Roofing Terms
Below is a glossary of roofing terms Rikcar Roofing & Siding uses. We are hoping this will make you more familiar, and comfortable with what we might speak with you about during any free estimates, or any information you might read on a work invoice you receive. You can also type in the search field below for the word/term your looking for as well.
Accelerated Weathering - The process in which materials are exposed to a controlled environment where various exposures such as heat, water, condensation, or light are altered to magnify their effects, thereby accelerating the weathering process. The material’s physical properties are measured after this process and compared to the original properties of the unexposed material, or to the properties of the material that has been exposed to natural weathering.
Adhere - To cause two surfaces to be held together by adhesion, typically with asphalt or roofing cements in built-up roofing and with contact cements in some single-ply membranes.
Algae Discoloration - A type of black roof discoloration caused by algae. Sometimes referred to as fungus growth
Application Rate - The quantity (mass, volume, or thickness) of material applied per unit area.
Asphalt - A bituminous waterproofing agent applied to roofing materials during manufacture.
Backsurfacing - Fine mineral matter applied to the back side of shingles to keep them from sticking together, such as talc, dolomite and mineral fines.
Base Flashing (membrane base flashing) - Plies or strips of roof membrane material used to close-off and/or seal a roof at the roof-to-vertical intersections, such as at a roof-to-wall juncture. Membrane base flashing covers the edge of the field membrane. (Also see Flashing.)
Base Ply - The lowermost ply of roofing in a roof membrane or roof system.
Blind-Nailing - The use of nails that are not exposed to the weather in the finished roofing system.
Bridging - A method of re-roofing with larger-sized shingles.
Bundle - An individual package of shakes or shingles.
CAN - This designation in front of a CSA, CGSB or ULC represents that it is a Canadian national standard.
Canopy - Any overhanging or projecting roof structure, typically over entrances or doors. Sometimes the extreme end is unsupported.
Cap Flashing - Usually composed of metal, used to cover or shield the upper edges of the membrane base flashing, wall flashing, or primary flashing. (See Flashing and Coping.)
Caulking - The physical process of sealing a joint or juncture; (2) sealing and making weather-tight the joints, seams, or voids between adjacent units by filling with a sealant.
Closed Cut Valley - A method of valley treatment in which shingles from one side of the valley extend across the valley while shingles from the other side are trimmed 50 mm (2″) from the valley centerline. The valley flashing is not exposed.
Concealed Nail Method - Application of roll roofing in which all nails are driven into the underlying course of roofing, and covered by a cemented, overlapped course. Nails are not exposed to the weather.
Counter Flashing - Formed metal sheeting secured on or into a wall, curb, pipe, rooftop unit, or other surface, to cover and protect the upper edge of the membrane base flashing or underlying metal flashing and associated fasteners from exposure to the weather.
Course - A row of shingles or roll roofing running the length of the roof.
CSA - Canadian Standards Association. A voluntary organization concerned with development of consensus standards, testing procedures and specifications.
Cure - A process whereby a material is caused to form permanent molecular linkages by exposure to chemicals, heat, pressure, and/or weathering.
Cure Time - The time required to effect curing. The time required for a material to reach its desirable long-term physical characteristics.
Dome - A roof that is shaped like a half-circle, or a variation of one.
Double Coverage - Application of asphalt roofing such that the lapped portion is at least 2″ (50 mm) wider than the exposed portion, resulting in two layers of roofing material attached to the deck.
Downspout - A conduit used to carry runoff water from a scupper, conductor head, or gutter of a building to a lower roof level, or to the ground or storm water runoff system. Also called a Leader.
Drip Edge - A metal flashing, or other overhanging component, with an outward projecting lower edge, intended to control the direction of dripping water and help protect underlying building components. A drip edge also can be used to break the continuity of contact between the roof perimeter and wall components to help prevent capillary action.
Eave - A projecting edge of a roof that extends beyond the supporting wall.
Edging Strips - Boards nailed along eaves and rakes (after cutting back existing wood shingles) to provide secure edges for re-roofing with asphalt shingles.
Elastomeric Coating - A coating system which, when fully cured, is capable of being stretched at least twice its original length (100% elongation) and recovering to its original dimensions.
Exposed Nail Method - Application of roll roofing in which all nails are driven into the cemented, overlapping course of roofing. Nails are exposed to the weather.
Exposure - The traverse dimension of a roofing element or component not overlapped by an adjacent element or component in a roof covering. The typical exposure for a standard-size, 3-tab shingle is 5 inches (127mm), depending upon manufacturer specifications.
Fascia - A vertical or steeply sloped roof or trim located at the perimeter of a building. Typically, it is a border for the low-slope roof system that waterproofs the interior portions of the building.
Fiberglass Mat - An asphalt roofing base material manufactured from glass fibers.
Flaking - Detachment of a uniform layer of a coating or surface material, usually related to internal movement, lack of adhesion, or passage of moisture.
Flashing - Components used to weatherproof or seal the roof system edges at perimeters, penetrations, walls, expansion joints, valley, drains, and other places where the roof covering is interrupted or terminated. For example, membrane base flashing covers the edge of the field membrane, and cap flashings or counterflashings shield the upper edges of the base flashing.
Flood Test - The procedure where a controlled amount of water is temporarily retained over a horizontal surface to determine the effectiveness of the waterproofing.
Gambrel - A roof that has two pitches on each side.
Gravel - Aggregate resulting from the natural erosion of rock.
Granules - Ceramic-coated colored crushed rock that is applied to the exposed surface of asphalt roofing products. Granules protect the asphalt coating from the sun’s rays, add color to the product and enhance fire resistance.
Gutter - A channeled component installed along the downslope perimeter of a roof to convey runoff water from the roof to the drain leaders or downspouts.
Headlap - Shortest distance from the butt edge of an overlapping shingle to the upper edge of a shingle in the second course below. The triple coverage portion of the top lap of strip shingles.
Hip - The inclined external angle formed by the intersection of two sloping roof planes.
Hip Roof - A roof that rises by inclined planes to form one or more hips.
HVAC - Heating, ventilating, and air conditioning equipment.
Ice Dam - Condition formed at the lower roof edge by the thawing and re-freezing of melted snow on the overhang. Can force water up and under shingles, causing leaks.
Impact Resistance - The ability of a roofing material to resist damage (e.g., puncturing) from falling objects, application equipment, foot traffic, etc. The impact resistance of the roofing assembly is a function of all of its components, not just the membrane itself.
Interlocking Shingles - Individual shingles that mechanically attach to each other to provide wind resistance.
Joist - Any of the small timbers, metal or wood beams arranged parallel from wall to wall to support a floor, ceiling, or roof of a building.
Laminated Shingles - Strip shingles containing more than one layer of tabs to create extra thickness. Also called three-dimensional shingles or architectural shingles.
Lap - That part of a roofing, waterproofing, or flashing component that overlaps or covers any portion of the same or another type of adjacent component.
Latex - A colloidal dispersion of a polymer or elastomer in water which coagulates into a film upon evaporation of the water.
Leader - Refer to Downspout.
Low Slope Application - Method of installing asphalt shingles on roof slopes 2:12 (9.5°) – 4:12 (18.4°).
Mansard Roof - A steeper roof that terminates into a flat roof at its high point.
Membrane - A flexible or semi-flexible material, which functions as the waterproofing component in a roofing or waterproofing assembly, and whose primary function is the exclusion of water.
Metal Flashing - Accessory components fabricated from sheet metal and used to weatherproof terminating roof covering edges. Frequently used as through-wall flashing, cap flashing (coping), counterflashing, step flashing, etc. Refer to Flashing.
Neoprene - A synthetic rubber (polychloroprene) used in liquid-applied and sheet-applied elastomeric roof membranes or flashings.
Nesting - A method of roofing with new asphalt shingles over old shingles in which the top edge of the new shingle is butted against the bottom edge of the existing shingle tab.
Night Seal (or Night Tie-Off) - A material and/or method used to temporarily seal a membrane edge during construction to protect the roofing assembly in place from water penetration. Usually removed when roofing application is resumed.
Offset - The distance between the edge of one shingle course and the edge of the next successive shingle course.
Open Valley - A method of valley construction in which the steep-slope roofing on both sides are trimmed along each side of the valley, exposing the valley flashing.
Organic Shingle - An asphalt shingle reinforced with material manufactured from cellulose fibers.
Parapet Wall - That part of a perimeter wall immediately adjacent to the roof which extends above the roof.
Plastic Cement - A roofing industry generic term used to describe Type I asphalt roof cement that is a trowel-able mixture of solvent-based bitumen, mineral stabilizers, other fibers and/or fillers. Generally, intended for use on relatively low slopes — not vertical surfaces.
Ponding - The excessive accumulation of water at low-lying areas on a roof.
Rake - The sloped edge of a roof at or adjacent to the first or last rafter.
Release Tape - A plastic film strip that is applied to the back of self-sealing shingles. This strip prevents the shingles from sticking together in the bundles only, and does not need to be removed for application.
Ridge - The upper most, horizontal external angle formed by the intersection of two sloping roof planes.
Rise - The vertical distance from the eaves line to the ridge.
Roll Roofing - Smooth-surfaced or mineral-surfaced, coated, prepared felts.
Roof Jack - A metal bracket used to support toe-boards on steep-slope roofs.
Run - Horizontal dimension of a slope.
Self-Sealing Shingle - An asphalt shingle containing factory-applied strip or spots of heat sensitive adhesive intended to adhere the overlying shingle once installed on the roof and warmed by the sun.
Shed Roof - A roof containing only one sloping plane. Has no hips, ridges, or valleys.
Shading - Slight differences in shingle color that may occur as a result of normal manufacturing operations.
Sill - The bottom horizontal framing member of an opening, such as below a window or door.
Sill Flashing - A flashing of the bottom horizontal framing member of an opening, such as below a window or door.
Skylight - A roof accessory, set over an opening in the roof, designed to admit light. Normally transparent, and mounted on a raised framed curb.
Slope - The degree of roof incline expressed as the ratio of the rise, in inches, to the run, in inches. (e.g. 18.5° (4:12) slope)
Soffit - The finished underside of eaves
Soffit Vent - A premanufactured or custom built air inlet source located at the downslope eave or in the soffit of a roof assembly.
Step Flashing - Individual pieces of material used to flash walls, around chimneys, dormers, and such projections along the slope of a roof. Individual pieces are overlapped and stepped up the vertical surface.
Tab - The exposed portion of strip shingles defined by cutouts.
Tie-Off - The transitional seal used (in roofing and waterproofing) to terminate a roofing or waterproofing application at the top or bottom of flashings, or by forming a watertight seal with the substrate, membrane or adjacent roofing or waterproofing system.
Tongue and Groove Planks - One of the oldest types of dimensional structural wood used as roof decking. The sides are cut with convex and concave grooves so adjacent planks may join in alignment with each other to form a uniform roof deck.
Underlayment - An asphalt-saturated felt or other sheet material (may be self-adhering) installed between the roof deck and the roof system, usually used in a steep-slope roof construction. Underlayment is primarily used to separate the roof covering from the roof deck, to shed water, and to provide secondary weather protection for the roof area of the building.
Valley - The internal angle formed by the intersection of two sloping roof planes.
Vent - An opening designed to convey air, heat, water vapor or other gas from inside a building or a building component to the atmosphere.
Weep Holes - Small openings whose purpose is to permit drainage of water that accumulates inside a building component (e.g., a brick wall, skylight frame, etc.).
Wind Uplift - The force caused by the deflection of wind at roof edges, roof peaks or obstructions, causing a drop in air pressure immediately above the roof surface. This force is then transmitted to the roof surface. Uplift may also occur because of the introduction of air pressure underneath the membrane and roof edges, where it can cause the membrane to balloon and pull away from the deck.
Woven Valley - Method of valley construction in which shingles from both sides of the valley extend across the valley and are woven together by overlapping alternate courses as they are applied. The valley flashing is not exposed.