Roofing Terms...
Architectural shingles - A steep slope system that is used for visual impact or aesthetics and typically requires a supporting deck with a minimum slope of 3:12. Architectural shingles usually have low seam heights of 1 inch to 1.5 inches and do not use sealant between seams. Due to the low seam height and no sealant in the seams, architectural shingles shed water but are not watertight and therefore require an underlayment below the shingles to create a watertight system.
Asphalt - 1) A bituminous waterproofing agent applied to roofing materials during manufacturing. 2) A dark brown to black cementitious material in which the predominating constituents are bitumens which occur in nature or are obtained in petroleum processing. 3) An organic bituminous compound used in the manufacturing of composition shingles.
Asphalt Roofing Cement - A substance used to bond roofing materials, also known as flashing cement or mastic.
American Society for testing of Materials (ASTM) - A voluntary organization concerned with the development of standards, testing procedures, and specifications. Many city building codes use ASTM standards.
Base Flashing - The portion of the flashing which is attached to, or rest on the roof deck.
Blend - Mixtures of various colored granules on the surface of shingles.
Blind Nailing - Nails driven in such a way that the heads are concealed by succeeding layers of roofing materials.
Blisters - Bubbles that may appear on the surface of asphalt roofing after installation.
Bridging - A method of reroofing where the new shingles follow the contour of the old roofing, also called "butting up". It is almost always desirable to tear off old roofing.
Built-Up Roofing - a flat or low-sloped roof made up of layers of asphalt and ply sheets (AKA BUR).
Bundle - A package of shingles. Usually, there are 3, 4 or 5 bundles per square.
Butt - The portion of the shingle exposed to the weather, sometimes called the "tab" of the shingle.
Butt edge - The lower edge of the shingle tabs.
Can’t Strip - A 45 degree beveled wood, fiberboard, or metal strips at the junction of the roof and a vertical surface used to break a right angle. Primarily used in low-sloped roofing.
Cap Flashing - The flashing on a vertical surface to prevent the flow of water from getting behind the base flashing. The cap flashing overlaps the base flashing. This flashing (AKA counter flashing) is generally not changed in a reroofing job.
Caulk - verb: To fill a joint with mastic or asphalt cement to prevent leaks. noun: A substance used to fill a joint or void.
Cement - A substance, when cured, binds two surfaces together.
Class "A" - The highest fire resistance rating for roofing as per ASTM E:108. Shingle with this rating should withstand severe exposure to fire from sources originating outside the building. Other classed are B and C.
Class "B" - Fire resistance rating that indicates roofing materials are able to withstand moderate exposure to fire originating from sources outside the building.
Closed Valley - When roofing materials cover the entire valley.
Coating - A layer of viscous asphalt applied to shingles in which granules are embedded.
Collar - Preformed flange placed over a vent pipe to seal the roof around the vent pipe opening. Also called a vent sleeve.
Collars - preformed flange placed over a vent pipe. (AKA vent sleeve) There are two types, lead jacks and rubber boots.
Condensation - The change of water from vapor to liquid when warm, moisture laden air comes in contact with a cold surface.
Counter flashing - That portion of the flashing attached to a vertical surface to prevent water from migrating behind the base flashing.
Course - A horizontal row of shingles or roll roofing running the length of the roof.
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.
Cricket - A small peaked saddle constructed on the top of the basic roof and behind the chimney. A cricket is generally not required.
Cupola - A structure rising above the main roof. It is usually ornamental, but may be used for ventilation.
Dead Level - A roof or section of roof without any pitch.
Dead Valley - A "dead valley" is where the downhill edge of a roof section joins the downhill edge of an opposing roof section so that the valley created is virtually flat. Water flowing down those two sections will end up at the bottom of this valley and have to flow sideways to exit the valley. Typically the bottom of a dead valley is covered with custom soldered sheet metal, or a hot tar system.
Deck - The surface installed over the supporting framing members to which the roofing is applied. The material installed over the framing of a structure on which shingles are installed. The primary materials are Oriented Strand Board (OSB) and CDX Plywood.
Dormer - A framed window unit projecting through the sloping plane of a roof.
Double Coverage - A method of applying roof shingles so that two complete layers of material are provided.
Down Spout - A pipe for draining water from roof gutters. Also called a leader.
Drip Edge - A non-corrosive, non-staining material (usually metal) used along the eaves and rakes to allow water runoff to drip clear of underlying construction.
Drip Course - The first course of shingles that slightly overhangs the edge.
Eave - The horizontal edge of a roof that projects over the outside wall.
Efflorescence - A deposit or encrustation of soluble salts, generally white and most commonly consisting of calcium sulfate, that may form on the surface of stone, brick, concrete or mortar when moisture moves through and evaporates on the masonry. Often caused by free alkalis leached from mortar, grout or adjacent concrete.
Expansion joint - A structural separation between two building elements designed to allow structural movement without damage to the roofing or waterproofing system.
Exposure - The portion of the shingle that is exposed to the weather. Usually measured from the butt of one shingle to the butt of the next overlapping shingles.
Exposure - The length of each shingle, shake, slate, etc. exposed to the weather, i.e., not covered by the next above course. Exposure is expressed in inches.
Fascia - A flat horizontal band beneath the eave edge of a sloped roof to which gutters are normally attached.
Felt - Fibrous material saturated with asphalt and used as an underlayment or sheathing paper.
Fiberglass Mat - An asphalt roofing base material manufactured from glass fibers.
Fire resistance - The ability of a roof top material to act as a barrier to the spread of fire and confine it to the area of origin. There are established test procedures for external fire exposure to classify roof systems into Class A, B, or C ratings. Underwriters Laboratories test method 790 established this procedure which ASTM adopted and named ASTM E:108. Therefore UL 790 and ASTM E:108 are the same test with different names. Factory Mutual and Warnock Hersey both use ASTM E:108 as the primary test for fire resistance.
Flashing - Pieces of metal or roll roofing used to prevent seepage of water into a building around any intersection or projection in a roof such as vent pipes, chimneys, adjoining walls, dormers and valleys. Galvanized metal flashing should be minimum 28 gauge for residential construction.
Gable - The upper portion of a side wall that comes to a triangular point at the ridge of a sloping roof.
Gable roof - A type of roof containing sloping planes on each side of the ridge. Contains a gable at each end.
Granules - Ceramic coated colored crushed rock that is applied to the exposed surface of asphalt composition roofing products.
Gutter - The trough that channels water from the eaves to the down spouts.
Hip - The inclined external angle formed by the intersection of two sloping roof planes. Runs from the ridge to the eaves.
Hip roof - A type of roof containing sloping planes on many or all sides. Contains few or no gables.
Ice dam - Condition formed at the lower roof edge or in valleys by the thawing and re:freezing of melted snow or ice on the overhang or in gutters. Can force water up and under shingles and underlayment causing leaks.
Laminated shingles - Strip shingles containing more than one layer of tabs to create extra thickness. Also called dimensional shingles or architectural shingles.
Lap - verb: To place or lay a layer of material so as to cover part of another overlap. Noun: The amount by which a piece of material overlaps another. A continuous ply of material laid on a roof. noun: The overlap of surface of one roofing material to another.
Lock Shingles - Shingles with a mechanical locking feature. These are not common.
Low slope application - Method of installing asphalt shingles on roof slopes between two and four inches per foot.
Mansard Roof - A vertical portion of roofing. A type of roof containing two sloping planes of different pitch. The lower plane has a much steeper pitch than the upper, often approaching vertical.
Mastic - See asphalt roof cement.
Nesting - See bridging
Normal Slope Application - A method of installing shingles between 4 and 21 inches per foot.
Open Valley - A valley in which metal is used and roofing material does not cover entire valley area as in a Closed Valley. Method of valley construction in which shingles on both sides of the valley are trimmed back from the center line on each side of the valley. Shingles do not extend to the center of the valley. Valley flashing is exposed down the centerline from top to bottom.
Overhang - The portion of the roof structure that extends beyond the exterior walls of a building.
Penetration - Any object such as a pipe that goes through the roof membrane.
Pitch - The degree of roof incline expressed as the ratio of the rise, in inches, to the span, in inches. Example: an incline expressed as an 8/12 would indicate a rise in the roof of 8 inches for every 12 inches of horizontal span.
Pond - A roof surface that is incompletely drained.
Radiant Barrier Decking - Foil backed plywood or wafer board sheathing that reflects up to 97% of the sun's radiant heat. It can lower attic temperatures and improve energy efficiency. You can increase indoor comfort while potentially reducing cooling energy costs.
Rafter - The supporting framing member immediately beneath the deck, sloping down from the horizontal ridge to the wall plate.
Rake - The inclined edge of a sloped roof over a wall.
Reglet - A groove in a wall or other surface adjoining a roof surface for the attachment of counterflashing.
Ridge - The uppermost, horizontal external angle formed by the intersection of two sloping roof planes.
Ridge shingles - Shingles used to cover the horizontal external angle formed by the intersection of two sloping roof planes.
Saturant - Asphalt used to impregnate felt for waterproofing and strength.
Seal Down - A factory applied asphalt strip used to bond a shingle to the one above. This is used to provide wind resistance.
Self-sealing shingles - Shingles containing factory applied strips or spots of self sealing adhesive.
Sheathing - Exterior grade boards used as a roof deck material, such as plywood, OSB, 1x4 and 1x6 dimensional lumber.
Shingle - noun: A small unit of prepared roofing material designed for installation with similar units on overlapping rows on inclines normally exceeding 4 inches of rise per 12 inches of span. Verb: To cover with shingles. To apply any sheet material in overlapping rows like shingles.
Side Lap - a horizontal lap.
Skirt Flashing - A large often single piece of flashing commonly found at the bottom of a dormer or addition.
Slope - The degree of roof incline expressed as the ratio of the rise, in inches, to the span or run, in inches. See "Pitch."
Soffit - The finished underside of the eaves.
Soffit Vent - An under eve opening needed for intake of outside air. These are not part of a typical roofing job, but are needed for good attic ventilation.
Soil Stack - A vent pipe that penetrates the roof.
Span - The horizontal measurement from eave to eave.
Spire - A tower of roof tapering up to a point.
Square - A unit of roof measure covering 100 square feet.
Square Butt Shingles - Generally three tab 20 year shingles : not laminated.
Standing Seam - Is a term used to describe the adjoining of two metal panels together with an upturned portion of the metal. The two panels are held together with concealed clips. The joinery raises the seam above the drainage plain. Standing seam systems are made out of metal.
Starter Course - The first course of shingles installed on your roof. It will be under the first exposed row. Often these shingles are 20 year three tab shingles. So as to not create an awkward hump, these are used even when heavier laminated shingles are installed.
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. Also called undercourse.
Step Flashing - Flashing along a roof slope against a wall or chimney using succeeding courses of flashing material placed in conjunction with layers or courses of roofing materials. Step Flashing is generally in 4 by 4 by 8 inch pieces. Flashing application method used where a vertical surface meets a sloping roof plane. Often called "tin shingles."
Substrate - The surface upon which the roofing or waterproofing membrane is placed, i.e. structural deck or insulation.
Tab - portion of strip shingles defined by cut outs or slots so when installed, material appears to be individually applied.
Undercourse - Shingles or material applied at the eaves under the first course of roofing material that provides protection by filling in the spaces or joints of the first course of shingles or roofing material.
Underlayment - Asphalt saturated felt, rubber membrane or other material used beneath roofing to provide additional protection for the deck. Asphalt saturated felt applied over the roof deck and under the roofing material.
UV Resistance - The ability of a roof top material to prevent degradation caused by exposure to Ultraviolet rays. Heat and UV are two primary causes of premature roof failure. UV rays cause the oils in a roofing membrane to dry out. These oils provide pliability and the membrane begins to crack when they are dried out. The addition of unique polymer blends provides protection to the membrane from cracking by maintaining the membrane's pliability. The resistance to UV degradation prolongs the waterproofing life of the membrane.
Valley - The internal angle formed by the intersection of two sloping roof planes.
Vent - Any outlet for air that protrudes through the roof deck such as a pipe or stack. Any device installed on the roof, gable or soffit for the purpose of ventilating the underside of the roof deck. Most roof systems should have intake and exhaust vents.
Weathering - Changes in color, texture or efficiency brought about by exposure to outside elements.
Wind Uplift - A wind uplift rating is not the miles per hour of wind speed a roof system can withstand, but rather, the negative pressure (pounds per square foot) that occurs when the inside air pressure of a building is greater than the air pressure outside the building. As wind passes over a building, there is a decrease in external air pressure on the roof and some down wind surfaces. As this external decrease in air pressure occurs, there is a corresponding increase in air pressure differential between the inside and the outside of the building. As the internal air pressure tries to equalize itself with the external pressure, the resulting force, identified as wind uplift forces, attempts to lift the roof off the building. Most parts of North America require a 1:60 or 1:90 uplift resistance. Coastal regions and high wind areas may require additional uplift resistance.
Woven valley - Method of valley construction in which shingles from both sides of the valley extend across the valley and are woven together on each side of the center line by overlapping alternate courses as they are applied. The valley flashing is not exposed.
