Industry-Standard Roofing Terms and Definitions

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The following is a list of roofing industry terms and definitions:

  • Asphalt: a bituminous waterproofing agent applied to roof materials during manufacturing
  • Asphalt roof cement: a mixture of solvent-based bitumen, mineral stabilizers, other fibers or fillers
  • Architectural shingle: a shingle that offers a dimensional appearance
  • Ballast: an anchoring material, such as precast concrete pavers, which allows gravity to hold single-ply roof membranes in place
  • Base flashing: the flashing provided by upturned edges of a watertight membrane on a roof; base flashing can be any metal or composition flashing at the joint between a roofing surface and a vertical surface, such as a wall or parapet
  • Base sheet: a coated felt used as the first ply in some multi-ply built-up and modified bitumen roof membranes
  • Batten: a cap or cover in a metal roof set over, or covering the joint between, adjacent metal panels
  • Bitumen: any material composed principally of bitumen, typically asphalt or coal tar
  • Blisters: bubbles or holes that can appear on the surface of asphalt roofing after installation
  • Buckle: the result of asphalt shingles not lying flat either from wrinkling of the roofing underlayment or movement of the roof deck
  • Building codes: sets of regulations governing the design, construction, alteration, and maintenance of structures that specify the minimum requirements to adequately safeguard the health, safety, and welfare of building occupants
  • Built-up roof: a flat or low-slope roof with multiple layers of asphalt and ply sheets
  • Bundle: an individual package of roofing shingles; there are typically 3, 4, or 5 bundles per roofing square (100 square feet)
  • Butt edge: the lowest edge of each shingle tab
  • Cant Strip: a strip of wood or similar material that serves as a transitional plane between the horizontal surface of a roof deck and a vertical surface
  • Caulk: a sealant material used to fill a joint to prevent leaks
  • Chalk line: a temporary line drawn on a roof used for alignment purposes, made by snapping a string or cord dusted with chalk
  • Class “A”: the highest rating for fire-resistance for roofing, as determined per ASTM E108; this rating indicates that a roof can withstand extreme exposure to fire starting from a source outside the building
  • Class “B”: fire-resistance rating that means roofing materials can withstand moderate exposure to fire starting from sources outside the building
  • Class “C”: fire-resistance rating that means roofing materials can withstand light exposure to fire arising from sources outside the building
  • Class 4 Impact Resistant shingle: shingles that achieve the roof industry’s highest ratings for impact resistance, UL 2218. Homeowners often qualify for an insurance premium discount.
  • Coating: a fully adhered, fluid applied roofing membrane applied on top of an existing flat-roof product to solve roof leaks and extend the life of an existing roof
  • Collar: a pre-formed rubber or metal flange inserted on top of a vent pipe to seal the roof around the pipe opening
  • Condensation: water which collects on a surface when warm, moist air comes in contact with a cold surface
  • Coping: the top covering of an exterior roof wall, typically made of metal, masonry, or stone
  • Counterflashing: the portion of flashing attached to a vertical surface to prevent water damage
  • Course: a row of shingles that extends the length of a roof
  • Cricket: a ridge construction at the back of a chimney designed to help deflect water away from a chimney
  • Deck: the surface installed over the roof frame to which roofing is applied
  • Dormer: a window that projects vertically from a sloping roof
  • Downspout: a pipe designed to drain water from roof gutters
  • Drip edge: a non-corrosive metal used along a roof’s eaves and rakes to allow water runoff to drip clear of the underlying construction
  • Eaves: the horizontal edge of a sloped roof, typically where gutters exist
  • Elastomeric Coating: a roof coating that is approximately ten times thicker than paint and forms an incredibly dense, yet flexible, cover that helps waterproof the exterior of a structure
  • EPDM: Ethylene Propylene Diene Monomer, a synthetic rubber used in a range of applications including flat roof cover material
  • Fascia: a board that runs along the lower edge of the roof
  • Felt: a fibrous material that acts as an underlayment immediately above the roof deck
  • Fiberglass mat: an asphalt roofing material manufactured with glass fibers
  • Flashing: a piece of metal used to prevent unwanted water entry into a building at any roof intersection, such as vent pipes, chimneys, and valleys
  • Flashing cement: roof cement is a multi-purpose patching material and adhesive for repairing holes and leaks in roofs, fixing rust spots and joints in leaky gutters and metal trim, and stopping leaks in flashing around chimneys, valleys and coping; it also is used to glue down loose asphalt shingles and fill cracks in concrete
  • Gable: the vertical triangular end of a building from the eaves to the ridge
  • Gable roof: a roof type with a sloping plane on each side of a single ridge and a gable at each end
  • Granules: ceramic-coated colored crushed rock adhered to the exposed surface of asphalt roofing shingles
  • Gutter: a trough that acts as a water distribution system to remove water from the roof eaves into the downspouts
  • Hip: the inclined external angle formed at the intersection of two sloping roof planes, which extends from the eaves to the ridge
  • Hip roof: a roof type where all sides slope downwards to the walls; a hip roof has no gables or vertical sides to the roof
  • Hip shingles: shingles installed to cover the inclined external angle formed at the intersection of two sloping roof planes
  • Ice dam: a condition formed at the lower roof edge by the thawing and refreezing of melted snow on the overhang that can force water up and under shingles, causing leaks
  • Laminated shingles: shingles with multi-dimensional layers to create extra thickness; also called architectural or dimensional
  • Low slope application: the method of installing asphalt shingles on roof slopes between two and four inches per foot
  • Louver: a slanted opening for ventilation
  • Mansard roof: a four-sided hip roof characterized by two slopes on each of its sides with the lower slope, punctured by dormer windows, at a steeper angle than the upper
  • Mastic: a roofing product used to seal a roof so water cannot penetrate. Several different kinds of products referred to as mastic; generally speaking, roof mastics are sticky, drying to a soft, rubbery finish after they are applied and allowed to cure.
  • Metal flashing: an accessory component fabricated from sheet metal and used to weatherproof terminating roof covering edges, typically used with cap flashing (coping), counterflashing, step flashing, etc.
  • Mil: a unit of measure often used to indicate the thickness of a roofing membrane
  • Mineral-surfaced roofing: asphalt shingles and roll roofing covered with granules
  • Modified bitumen: a roof coating made of bitumen using special combinations of polymers to modify the underside of the sheet
  • Natural ventilation: a ventilation system utilizing ventilators in an attic to leverage the natural airflow to remove hot or moist interior air and replace it with fresh outside air
  • Normal-slope application: the roofing installation method on roof slopes between 4 inches and 21 inches per foot
  • Open valley: the method of valley construction in which shingles on both sides of a valley get trimmed, and the valley flashing is exposed
  • Oriented strand board (OSB): a type of engineered wood similar to particle board, formed by adding adhesives and then compressing layers of wood strands in specific orientations
  • Organic felt: a roofing base material manufactured from cellulose fibers
  • Parapet wall: the extension of a wall at the edge of the roof that extends above the roof
  • Pitch: the measurement degree of roof incline expressed as the ratio of rise over run, in feet
  • Ply: the number of layers of roofing
  • Ponding: water accumulation at low-lying areas on a roof
  • Rafter: the supporting framing immediately beneath the roof deck, sloping from the ridge to the wall
  • Rake: the inclined edge of a roof, from the eave edge to the ridge
  • Ridge: the highest point on a roof represented by a horizontal line where two opposing roof areas intersect
  • Ridge vent: a roof vent positioned at the ridge that allows warm or moist air to escape from the attic area
  • Ridge shingles: shingles installed to cover the horizontal ridgeline
  • Rise: the vertical distance from a roof eave to the ridgeline
  • Roll roofing: asphalt roofing material that is manufactured and installed in roll form
  • Roof assembly: a roofing system that consists of a roof covering and roof deck or a single component serving as both the roofing covering and the roof deck; a roof assembly includes the roof deck, vapor retarder, substrate or thermal barrier, insulation, and roof covering
  • ​Roof covering: the covering applied to the roof deck for weather resistance, fire classification, or appearance
  • Roof deck: the flat or sloped surface constructed on top of the exterior walls of a building or other support structures for the purpose of enclosing the story below, or sheltering an area, to protect it from the elements
  • Roofing contractor: a roofer or roofing contractor is a tradesperson who specializes in roof construction across a variety of materials, focused on roof replacement, restoration, and repair
  • Roof penetrations: most roofs are punctured with holes or penetrations that must be properly sealed to avoid water penetration such as chimneys, pipes, skylights, exhaust fans, vents, and air conditioning units
  • Roof recover: the process of installing an additional roof covering over a prepared existing roof covering without removing the existing roof covering; also referred to as re-roofing
  • Roof replacement: the process of removing the existing roof covering repairing any damaged substrate, and installing a new roof covering
  • ​Roof surface: the roof materials used to secure any type of roof cladding
  • Roof ventilation: the natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, attics, cathedral ceilings, or other enclosed spaces over which a roof assembly or roof system is installed.
  • Run: the horizontal distance from a roof eave to a point directly under the ridge
  • Seepage: dampness on a ceiling, especially in corners that are caused by either cracks in a roof or improper waterproofing of a roof
  • Sheathing: a strong layer of wood boards fixed to a roof’s joists and trusses; also known as roof decking
  • Shingle: an individual unit of prepared roofing material designed for installation in overlapping rows or courses on inclines typically exceeding 3:12 slope
  • Side lap: ​the area on rolled material where one roll overlaps the rolled material beneath it
  • Sidewall: a junction between a wall and a sloped portion of a roof
  • Slope: the measurement in degrees of roof incline expressed as the ratio of the rise over run
  • Soffit: the finished underside of the eaves
  • Square: a unit of roof measurement; one roofing square is equal to 100 square feet
  • Starter course: the first layer of roofing installed adjacent to the lowest perimeter of the roof area, also known as starter strip. With steep-slope water-shedding roof coverings, the starter course gets covered by the first course.
  • Step flashing: a flashing application that integrates the roof cladding into the exterior wall cladding to prevent water leaks
  • Synthetic underlayment: a premium type of underlayment with an extremely high tear strength compared to felt, which means less tearing around fasteners during roof installation and fewer opportunities for water infiltration
  • Tab: the exposed portion of three-tab or strip shingles defined by cutouts
  • Three-tab shingle: a single-layer shingle which has three tabs and a uniform appearance
  • UL: Underwriters Laboratories, LLC
  • Underlayment: one or more layers of felt that provide an additional moisture-resistant layer between the roof deck and roof shingles
  • Vapor retarder: a layer of material or a laminate used to appreciably reduce the flow of water vapor into a roof assembly
  • Valley: the angle formed where two roof slopes meet where water collects to flow off the roof
  • Vent: a device installed on a roof that protrudes through the roof deck, such as a pipe or stack, to ventilate the underside of the roof deck
  • Water vapor: air-transported water that can enter a building by the process of diffusion of water through the building envelope materials
  • Woven valley: the method of valley construction in which shingles from both sides of the valley get woven together

Contact Metro City Roofing today to schedule your free roof inspection.