California roofing terminology
Western Roofing Systems: Common roofing terms
Understanding the components of your roofing system will help you determine the style of your roof, identify interior space, and dictate where to add rooms, frame additions, and place chimneys. The roof also suggests the type of climate that the geographical location of the building receives. Not only will understanding the details of the roof help the builders responsible for the design, but it will also help the homeowners select the perfect roofing style for there location and personal taste. You will find some of the most important roofing terms defined below.
Aggregate: Loose surfacing material or ballast for a roof system.
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.
Asphalt Shingles: Composition roof shingles made from asphalt-impregnated felt covered with mineral granules.
Back Surfacing: Fine mineral matter applied to the back side of shingles to keep them from sticking.
Base flashing: That portion of the flashing attached to or resting on the deck to direct the flow of water onto the roof covering.
Battens: 1″x2″x4′ wood strips nailed to the roof, upon which the field tile hangs.
Birdstop: In addition to preventing birds from nesting in the hollows of the tile, this length of formed metal or foam elevates the first course of tile so that it is positioned at the same angle as subsequent courses.
Blisters: Bubbles that may appear on the surface of asphalt roofing after installation.
Boxed Eave: Horizontal overhang that runs from the eaves edge to the side of the building.
Built-up roof: A flat or low-sloped roof consisting of multiple layers of asphalt and ply sheets.
Bundle: A package of shingles. There are 3, 4 or 5 bundles per square.
Caulk: To fill a joint with mastic or asphalt cement to prevent leaks.
Chalk line: A line made on the roof by snapping a taut string or cord dusted with chalk. Used for alignment purposes.
Class A: The highest fire rating a roofing system can achieve; synonymous with fire proof.
Class “B”: Fire-resistance rating that indicates roofing materials are able to withstand moderate exposure to fire originating from sources outside the building.
Class “C”: Fire-resistance rating that indicates roofing materials are able to withstand light exposure to fire originating from sources outside the building.
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 two inches from the valley centerline. The valley flashing is not exposed.
Coating: A layer of viscous asphalt applied to the base material into which granules or other surfacing is embedded.
Collar: Pre-formed flange placed over a vent pipe to seal the roof around the vent pipe opening. Also called a vent sleeve.
Color-through: During manufacturing, the color is mixed throughout the roofing material to become an integral part of it. When the product is cut, the affected area shows the same color as the surface.
Composition Shingles: A thin, pressed roofing material made of asphalt impregnated fiberglass or organic mat, covered on one side with colored stone granules. Also called comp.
Concealed nail method: Application of roll roofing in which all nails are driven into the underlying course of roofing and covered by a cemented, overlapping course. Nails are not exposed to the weather.
Condensation: The change of water from vapor to liquid when warm, moisture-laden air comes in contact with a cold surface.
Cornice: The top set of moldings just below a roofline, usually consisting of a fascia board, a soffit and appropriate trim moldings.
Counter flashing: That portion of the flashing attached to a vertical surface to prevent water from migrating behind the base flashing.
Course: A row of shingles or roll roofing running the length of the roof.
Coverage: Amount of weather protection provided by the roofing material. Depends on number of layers of material between the exposed surface of the roofing and the deck; i.e., single coverage, double coverage, etc.
Cricket: A peaked saddle construction at the back of a chimney to prevent accumulation of snow and ice and to deflect water around the chimney.
Cutout: The open portions of a strip shingle between the tabs.
Deck: the structural base for the roof. Made of wood or plywood.
Dormer: A vertical opening coming through a sloping roof.
Dormer Rafter: Roof rafters, which frame the dormer roof.
Double coverage: Application of asphalt roofing such that the lapped portion is at least two inches wider than the exposed portion, resulting in two layers of roofing material over the deck.
Downspout: A pipe for draining water from roof gutters. Also called a leader.
Drip edge: A non-corrosive, non-staining material used along the eaves and rakes to allow water run-off to drip clear of underlying construction.
Dutch Hip Roof: Roof with the upper gable ends of the roof being built with a short hip section.
Dutch lap method: Application of giant individual shingles with the long dimension parallel to the eaves. Shingles are applied to overlap adjacent shingles in each course as well as the course below.
Eaves: the lower border of a roof that overhangs the wall.
Edging strips: Boards nailed along eaves and rakes after cutting back existing wood shingles to provide secure edges for reroofing with asphalt shingles.
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 part of each shingle that is exposed to the weather.
Fascia: Horizontal band or board that runs along the eaves of a roof.
Feathering strips: Tapered wood filler strips placed along the butts of old wood shingles to create a level surface when reroofing over existing wood shingle roofs. Also called horsefeathers.
Felt: A flexible sheet that is saturated with asphalt and used as an underlayment, sometimes called “tar paper”
Fiber-Cement: A roofing material that has cellulose(wood fiber) mixed into it. Cellulose absorbs water and can add greatly to the roof’s weight, while reducing its longevity.
Fiber glass mat: An asphalt roofing base material manufactured from glass fibers.
Flashings: a corrosion-resistant sheet metal used in waterproofing roof valleys or hips or the angle between a chimney and a roof.
Free-tab shingles: Shingles that do not contain factory-applied strips or spots of self-sealing adhesive
Gable: The triangular part of a building’s end wall. Also a type of roof.
Gambrel roof: A type of roof containing two sloping planes of different pitch on each side of the ridge. The lower plane has a steeper slope than the upper. Contains a gable at each end.
Granules: Ceramic-coated colored crushed rock that is applied to the exposed surface of asphalt roofing products.
Gutters: a trough along the eaves to catch and carry off rainwater.
HEX shingles: Shingles that have the appearance of a hexagon after installation.
Hip: the outside angle formed by the meeting of two sloping sides of a roof that have their supports running in different directions.
Hip roof: A type of roof containing sloping planes of the same pitch on each of four sides. Contains no gables.
Hip shingles: Shingles used to cover the inclined external angle formed by the intersection of two sloping roof planes.
Interlocking shingles: Individual shingles that mechanically fasten to each other to provide wind resistance.
Joists: any of the small timbers or metal beams ranged parallel from wall to wall in a structure to support a floor or ceiling.
Laminated shingles: Strip shingles containing more than one layer of tabs to create extra thickness. Also called three-dimensional shingles or architectural shingles.
Lap: To cover the surface of one shingles or roll with another.
Lap cement: An asphalt-based cement used to adhere overlapping plies of roll roofing.
Low slope application: Method of installing asphalt shingles on roof slopes between two and four inches per foot.
Life Cycle Cost: the total lifetime cost of a roof. Calculated by adding maintenance costs to the installed price, then deducting the added value the roof provides when the home is resold.
Low slope application: Method of installing asphalt shingles on roof slopes between two and four inches per foot.
Mansard: a type of roof on which there are two slopes on each side, with the lower slope much steeper than the upper one.
Mastic: An asphalt-based cement used to bond roofing materials. Also known as flashing cement
Metal Drip Edge: a narrow strip of non-corrodible metal used at the rake and eave to facilitate water runoff.
Mineral-surfaced roofing: Asphalt shingles and roll roofing that are covered with granules.
Nesting: A method of reroofing 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.
No-cutout shingles: Shingles consisting of a single, solid tab with no cutouts.
Non-prorated warranty: A warranty which provides full replacement costs for the item(s) covered during the full term of the warranty. In contrast, a prorated warranty merely reimburses a percentage of replacement costs, depending on the age of the roof.
Non-veneer panel: Any wood based panel that does not contain veneer and carries an APA span rating, such as wafer board or oriented strand board.
Normal slope application: Method of installing asphalt shingles on roof slopes between 4 inches and 21 inches per foot.
Open valley: Method of valley construction in which shingles on both sides of the valley are trimmed along a chalk line snapped on each side of the valley. Shingles do not extend across the valley. Valley flashing is exposed.
Organic felt: An asphalt roofing base material manufactured from cellulose fibers.
Overhang: That portion of the roof structure that extends beyond the exterior walls of a building.
Pallets: Wooden platforms used for storing and shipping bundles of shingles.
Parapet: A low protective wall that extends above the roofline or balcony for support.
Pitch: The angle of steepness of a roof.
Plastic Cement: a compound used to seal flashings and in some cases to seal down shingles as well as for other small waterproofing jobs. Where plastic cement is required for sealing down shingles, use a dab about the size of a half dollar unless otherwise specified.
Ply: The number of layers of roofing: i.e. one-ply, two-ply.
Racking: Roofing application method in which shingle courses are applied vertically up the roof rather than across and up. Not a recommended procedure.
Rake: A slightly less than 90 degree finishing tile installed on gable ends only; the outer edge of the roof from the eave to the ridge.
Rafters: any of the parallel beams that support a roof.
Random-tab shingles: Shingles on which tabs vary in size and exposure.
Release tape: A plastic or paper strip that is applied to the back of self-sealing shingles. This strip prevents the shingles from sticking together in the bundles, and need not be removed for application.
Re-roofing: The procedure of installing a new roof system.
Ridge: the line of intersection at the top between opposite slopes or sides of a roof.
Ridge shingles: Shingles used to cover the 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: Asphalt roofing products manufactured in roll form.
Roofing tape: An asphalt-saturated tape used with asphalt cements for flashing and patching asphalt roofing.
Run: The horizontal distance from the eaves to a point directly under the ridge. One half the span.
Saturant: Asphalt used to impregnate an organic felt base material.
Saturated felt: An asphalt-impregnated felt used as an underlayment between the deck and the roofing material.
Self-sealing Cement: a thermal sealing tab cement built into the shingle to firmly cement the shingles together automatically after they have been applied properly and exposed to warm sun temperatures. In warm seasons, the seal will be complete in a matter of days. In colder seasons, sealing time depends on the temperature and amount of direct sunlight hitting the shingles. Hand sealing with plastic cement should be done to ensure sealing in winter.
Selvage: That portion of roll roofing overlapped by the succeeding course to obtain double coverage.
Shading: Slight differences in shingle color that may occur as a result of normal manufacturing operations.
Sheathing: the first covering of boards or of waterproof material on the outside wall of a frame house or on a timber roof.
Shed roof: A roof containing only one sloping plane. Has no hips, ridges, valleys or gables.
Single coverage: Asphalt roofing that provides one layer of roofing material over the deck.
Slope: The degree of roof incline expressed as the ratio of the rise, in inches, to the run, in feet.
Smooth-surfaced roofing: Roll roofing that is covered with ground talc or mica instead of granules (coated).
Soffit: The finished underside of the eaves.
Soil stack: A vent pipe that penetrates the roof.
Span: The horizontal distance from eaves to eaves.
Specialty eaves flashing membrane: A self-adhering, waterproofing shingle underlayment designed to protect against water infiltration due to ice dams or wind driven rain.
Square: 100 square feet of roof area.
Square-tab shingles: Shingles on which tabs are all the same size and exposure.
Starter strip: Asphalt roofing applied at the eaves that provide protection by filling in the spaces under the cutouts and joints of the first course of shingles.
Steep slope application: Method of installing asphalt shingles on roof slopes greater than 21 inches per foot.
Step flashing: Flashing application method used where a vertical surface meets a sloping roof plane.
Strip shingles: Asphalt shingles that are approximately three times as long as they are wide.
Tab: the portion of the shingle set off by the cutouts. Also the part of the shingle that is exposed to the weather.
Tar Paper: see “Felt” above.
Telegraphing: A shingle distortion that may arise when a new roof is applied over an uneven surface.
Three-dimensional shingles: See “laminated shingles” above.
Three-tab Shingle: the most popular type of asphalt shingle-usually 12″x 36″ in size with three tabs.
Top lap: That portion of the roofing covered by the succeeding course after installation.
UL label: Label displayed on packaging to indicate the level of fire and/or wind resistance of asphalt roofing.
Underlayment: a layer of asphalt-saturated felt(sometimes referred to as tar paper) which is laid down on a bare deck before the shingles are installed.
Valley: the intersection of two sloping roofs joining at an angle to provide water runoff.
Vent: an opening through which outside air can enter the attic space forcing moisture laden air out. Ventilation helps prevent condensation problems that can adversely affect roofing and deck materials.
Vent sleeve: See collar.
Woawoaa: Roofer’s term for “I’ll be right down”.
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.