The ultimate glossary of all roofing and roofing-related terms all in one place.
Algae discoloration: Brown or black spots on a roof that are caused by algae growth. Also known as fungus growth.
Asphalt: A highly viscous black form of liquid or semi-liquid petroleum. In roofing, asphalt is used as a waterproofing and fireproofing agent. Also known as bitumen.
Asphalt plastic roofing cement: As a type of cement, this sealant is used to protect shingle roofs and bond roofing materials. It will waterproof a roof and keep it from getting sun-damaged. It is also known as mastic, flashing cement, and asphalt plastic.
Back surfacing: A coat of finely pulverized mineral such as sand, limestone, or talc that is put on shingles to keep them from sticking to one another.
Base flashing: Used at the joint between the vertical and roofing surface that protects a roof from being flooded by directing the water to the roof covering.
Blisters: Excessive heat from poorly ventilated roofs causes blisters or bubbles that can shorten a roof’s life. They typically appear within the first year of roof installation.
Built-up roof: A common roofing material often found on slope roofs. It consists of alternating layers of asphalt and reinforcing fabric.
Bundle: A package of shingles. The most common type is three bundles to a square, but there are also four and five.
Butt edge: The bottom edge of a shingle tab.
Caulking: Filling a joint with asphalt or mastic to prevent leakage.
Chalk line: A chalk line or chalk box is a tool used to mark long straight lines with a cord that’s been dusted in chalk or with an extremely taut string.
Class “A”: According to ASTM E108-17, it is the highest fire-resistance rating for roofs. If a roof has a Class A rating, it can last 2–4 hours before ignition and the maximum flame spread is 6 ft.
Class “B”: Roofing materials are effective under moderate fire exposure. Shingles and pressure-treated shakes usually fall under the Class B category.
Class “C”: The lowest fire-resistance rating that can endure only light fire exposure.
Closed cut valley: Shingles from one roof slope extend a few feet onto the slope next to it. The shingles from the adjacent slope are cut center and parallel to the valley.
Coating: Over the base material which has surfacing and granules embedded into it, a viscous layer of asphalt is applied.
Collar: An accessory that is placed over a vent pipe. Its purpose is to seal and/or cover vent pipes and other openings and penetrations.
Concealed nail method: A way of putting nails in a roof so that they’re not exposed to weather conditions. The nails are protected by overlapping roofing material.
Condensation: A natural process that occurs when water goes from vapor to liquid form when exposed to a temperature drop or a rise in atmospheric pressure.
Counter flashing: A piece of metal sheeting is attached to a rooftop unit that stops water from going behind the base flashing.
Course: A row of shingles that makes up the roofing, flashing, and waterproofing system.
Coverage: Any surface area that is covered by a specific warranty. There are several types of coverage that include single and double.
Deck: A structural component of a roof that supports the design dead and live loads.
Dormer: A framed window unit that projects through a roof’s sloping plane.
Downspout: A pipe that redirects and drains water from the gutters. Also known as a leader.
Drip edge: A non-corrosive metal flashing that is used along the rakes and eaves. It controls the direction of dripping water and protects the underlying elements of a building or house.
Eaves: The projecting edges of a sloped roof that extend beyond the supporting wall.
Eaves flashing: An additional protective layer of roofing material is added to the eaves. It is supposed to prevent roof damage from water backup.
Edging strips: Several boards that are nailed along rakes and eaves. They help with removing wood shingles and reroofing with asphalt ones.
Ell: A wing or an extension of a building or house that lies perpendicular to the main portion of the object.
Felt: A fibrous material made into a flexible sheet that comes in four types: glass, organic, asbestos, and polyester. It is most often used as a sheathing paper or as an underlayment.
Fiberglass mat: A rigid board or blanket insulation, made from glass fibers, and used to insulate walls and roofs.
Flashing: Metal components used to seal or waterproof roof system edges. The edges are sealed at all the perimeters, walls, drains, valley, vent pipes, and joints.
Flashing cement: Synonym for asphalt plastic roofing cement.
Gable: The top triangular part of a sidewall that tapers to a point above the eave line and under the sloping roof.
Gable roof: A type of single-edge roof that ends with gables.
Gambrel roof: A type of roof that has two pitches on each side, with a gable at each end.
Gutter: A channeled component that is installed along the downslope perimeter and that directs water from the eaves to the downspout.
Headlap: Represents the length from the upper edge of a shingle to the butt edge.
Hip: When two sloping roof planes intersect, they create an inclined external angle called a hip.
Hip roof: A type of roof that has sloping planes of the same pitch that form one or more hips.
Hip shingles: A type of shingles that cover the ridge of a roof. They are used on hip roofs.
Ice dam: A mass of ice that forms when melted snow on a roof’s surface starts to freeze. It forms at the lower roof edge and can force water under shingles.
Interlocking shingles: Single shingles that mechanically attach to one another to protect a roof from strong winds.
Laminated shingles: When strip shingles have more than one layer of tabs, they’re considered laminated. Also known as three-dimensional shingles.
Lap: A part of roofing that covers or overlaps any part of the adjacent components. It can also represent the act of covering one shingle roll with another.
Mansard roof: A type of steep roof that has no gables and terminates into a flat point at its highest part.
Nesting: The process of installing new asphalt shingles over old ones. Doing so will help prevent existing shingles from moving and becoming visible on the surface of a roof.
Normal slope application: A way to install asphalt shingles on a roof’s slopes so that they are between 4 and 21 inches apart per foot.
Open valley: Another type of valley construction where both sides of the steep-slope roofing are trimmed to expose the valley flashing. They are cut on each side of the valley, along a chalk box line.
Organic felt: A base material for asphalt roofing that is made from cellulose fibers.
Overhang: Part of a roof’s structure that protrudes beyond the side of the building. It protects the roof from different weather conditions.
Pallet: A platform, typically made from wood, that is used for shipping and storing roofing materials.
Pitch: A measurement that shows how much a roof rises for every 12 inches of depth.
Plastic cement: A generic term to describe Type I asphalt roof cement. It is a mixture of asphalt, mineral stabilizers, and other fibers intended for use on lower slopes.
Ply: Describes how many layers of felt and sheet there are on a roof.
Quick-setting cement: A type of cement that can set in 35 minutes. It is often used for special construction conditions, such as underwater, or to glue tabs of shingles together.
Rafter: A part of the sloped structural members, it extends from the ridge to the eave. A rafter’s purpose is to support a roof deck.
Rake: The sloped edge of a roof that is over a wall, measured from the ridge to the eave.
Release tape: A strip made of plastic or paper that is pressure sensitive and used to prevent self-sealing shingles from sticking together. It doesn’t need to be removed before application.
Ridge: A horizontal line that shows the highest point of a roof. It indicates where the two sloping roof planes intersect.
Ridge shingles: A unique type of shingles specially designed to cover the ridges of a roof and protect it from weather conditions.
Rise: A vertical dimension of a slope, measuring from the ridge to the eaves line.
Roofing tape: A type of heavy-duty tape that can fix and seal asphalt roofing and patching.
Run: A horizontal dimension of the roof that measures one half the span, from under the ridge to the eaves.
Saturated felt: A type of felt that has been saturated with low-softening point asphalt. It is used as an underlayment between the roofing material and the deck.
Self-sealing shingles: A type of shingle that has self-sealing adhesive on it in the form of strips or spots.
Self-sealing spot or strip: An adhesive that is used to glue shingle courses together.
Shading: A minor difference in surfacing colors on shingles. Often happens as a result of regular manufacturing operations.
Sheathing: Panels or boards used in wall, floor, and roof assemblies.
Single coverage: When roofing material over the deck has only one layer of asphalt roofing, it is considered to be single coverage.
Slope: The angle of an incline that can be expressed in percentages or as a ratio of the rise (in inches) to run (in feet).
Soffit: The enclosed or finished underside of an eave’s overhanging section.
Soil stack: A sanitation or vent pipe used in vent plumbing fixtures that goes through the roof.
Span: The horizontal distance from one side of the eaves to the other.
Specialty eaves flashing membrane: A type of waterproof shingle that is specifically designed to protect against extreme weather conditions and water infiltration.
Square: A roof unit measurement that covers 100 sq ft.
Starter strip: Shingle strips or roll roofing that is applied along the downslope of the eave line.
Steep slope application: A way to install asphalt shingles on roof slopes by placing them more than 21 inches per foot apart.
Step flashing: A flashing application method where individual pieces of material are placed along the slope of a roof.
Tab: The exposed part of strip shingles that are defined by cutouts.
Telegraphing: If a new roof is applied over an uneven surface, shingles may start to distort and cause telegraphing.
Three-tab shingle: A type of asphalt shingle that has three tabs and measures 12 inches by 36 inches in size.
Top lap: The part of a roof that is covered by a succeeding course. A top lap is done immediately after roof installation.
UL label: A label to show if and how fire or wind-resistant asphalt roofing is.
Underlayment: A sheet material, usually asphalt-saturated felt, that is installed between the roof system and deck. Most commonly, underlayment is used to separate the roof deck from the roof covering and provide additional protection for the latter.
Valley: The part where two sloping roof planes intersect to form an internal angle.
Vapor retarder: A material that is installed to restrict or impede the passage of water vapor.
Vent: An opening or outlet that is designed to convey heat, air, water vapor, or other gasses from inside a building.
Woven Valley: A type of valley construction and installing asphalt shingles where the two roof slopes intersect. The valley is completed when shingle courses overlap and look woven together.