Roofing Terms

Roofing Glossary

We’ve created this useful glossary to help increase your vocabulary and improve your knowledge of roofing terms as your roof is being installed within the Denver metro area. Our team offers quality roofing repair services including home hail damage repair, roof coating, reroofing, and more!


Crushed rock used as a top-layer in some flat-roof applications.

"L" flashing

Continuous metal flashing, consisting of several feet of metal. Used at horizontal walls; bent to resemble an L.


Rooftop fungus that can leave dark stains on roofing.

Angled Fasteners

Roofing nails and staples driven into decks at angles not parallel to the deck.

Apron Flashing

Metal flashing used on chimney fronts.


A bituminous waterproofing agent used in various types of rooting materials.

Asphalt Plastic Cement

Asphalt-based sealant material, meeting ASTM D4586 Type I or II. Used to seal and adhere roofing materials; also called MASTIC; BLACKJACK; ROOF TAR; and BULL.

Asphalt Concrete Primer

Asphalt-based primer used to prepare concrete and metal for asphalt sealant.


The American Society for Testing and Materials, an organization that sets standards for a wide variety of materials, including roofing.


Granular material added to the back of shingles to assist in keeping them separated during delivery and storage.

Base Sheet

Bottom layer of a modified or built-up roofing system.


Term commonly applied to various mixtures of naturally-occurring solid or liquid hydrocarbons, excluding coal.


Bubbles or pimples in roofing materials; usually moisture-related. In shingles, blisters are either moisture under the material or moisture trapped inside the material.


Occurs when shingles are subject to high winds and are forced off a roof deck.


A method of re-roofing with metric-sized shingles.


Occurs when a wrinkle or ripple affects shingles or their underlayments.

Built-up Roof

A type of commercial-, or, flat-, roof finish produced by applying alternate layers of roofing felt and hot asphalt or pitch. The top layer is given a hot flood coat of the bitumen; granules of rock, gravel, slag, or ceramic particles may be embedded while the flood coat is still hot. The roofing system may incorporate rigid insulation.


A package of shingles. There are three to five bundles per square.

Butt Edge

The lower edge of shingle tabs.

Cap Flashing

The portion of flashing attached to a vertical surface to prevent water from migrating behind the base flashing.

Cap Sheet

A top layer in a built-up or modified roofing system.


To fill a joint with mastic or asphalt plastic 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" Fire Resistance

The highest fire-resistance rating for roofing per ASTM E 108. Indicates that roofing is able to withstand severe exposure to fire originating from sources outside the building.

Class "B" Fire Resistance

Fire-resistance rating that indicates that roofing material is able to withstand moderate exposure to originating from sources outside the building.

Class "C" Fire Resistance

Fire-resistance rating that indicates that roofing material is able to withstand light exposure to 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.

Cold Process Adhesive

Mastic prepared with SBS modifiers to adhere laps, flashings, and joints of built-up or low-slope roofing without hot-mopping or torching equipment, or, the primary adhesive used to adhere the roofing membrane in a cold-applied roofing system.


Pre-formed flange placed over a vent pipe to seal the roofing above the vent pipe opening.

Composite Roofing

Roofing shingles made with a mixture of plastic and minerals. The shingles are driven into the underlying course of roofing and covered by a cemented overlapping course. Nails are not exposed to the weather. This is a popular choice for our Denver, Westminster, and Aurora roofing services.

Concealed Nail Method

Application of roll roofing in which all nails are driven into the underlying course or roofing and covered by a cemented overlapping course. Nails are not exposed to the weather.

Coping Joint

The intersection of a roof slope and an exterior vertical wall.


When rust, rot, or age negatively affect roofing metals.


The metal or siding material that is installed over roof-top base flashing systems.


A row of shingles or roll roofing running the length of the roof.


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, e.g. single coverage, double coverage, etc.


A peaked water diverter installed behind chimneys and other large roof projections. Effectively diverts water around projections.


When shingles are improperly installed over an existing roof, or are overexposed, they form a curl or cup.


The short elevation of an exterior wall above the deck of a commercial flat roof.


The substrate over which roofing is applied. Usually plywood, wood boards, or planks.


A raised roof extending of a larger roof plane.


An installed lip that keeps shingles up off of the deck at edges, and extends shingles out of over eaves and gutters, and prevents water from backing up under shingles.


The roof edge from the fascia to the structure’s outside wall. In general terms, the first three feet across a roof is termed the eave.


When installing rolled products in roofing, the area where a roll ends on a roof, and is overlapped by the next section of rolled material (underlayments, rolled roofing).


The area on any roofing material that is left exposed to the elements.


Nails or staples used in securing roofing to the deck. Felt-organic or paper-based rolled material saturated with asphalt to serve as roofing underlayment.


The Federal Housing Authority. Sets construction standards throughout the United States.

Fiberglass Mat

Fibers condensed into strong, resilient mats for use in roofing materials.


Metal pan extending up or down a roof slope around flashing pieces. Usually at chimneys and plumbing vents.


Material used to waterproof a roof around any projections throughout the roof deck.

Flashing Cement

Sealant designed for use around flashing areas, which is typically thicker than plastic cement.

Gable Roof

Traditional roof style, two-peaked roof planes meeting at a ridge line of equal size.

Gambrel Roof

A type of roof with a gable on either end, but with two sloping roof planes of different angles on either side, the lower of which is steeper than that of the upper. A common barn roof or mansard roof.


Crushed rock that is coated with a ceramic coating and fired. Used as a top surface on shingles.


The method to assure sealing of shingles on very steep slopes, in high-wind areas, and when installing in cold weather.

Head Lap

Shortest distance from the butt edge of an overlapping shingle to the upper edge of a shingle in the second course below it. The triple coverage portion of the top lap of strip shingles.

High Nailing

When shingles are nailed or fastened above the manufacturer’s specified nail location.

Hip Legs

The down-slope ridges on hip roofs.

Hip Roof

A roof with four roof planes coming together at a peak and four separate hip legs.

Ice Dam

When a snow load melts on a roof and re-freezes at the eaves. Ice dams force water to back up a roof and cause leakage.


The area where roll roofing or rolled underlayments overlap one another during application.

Low Slopes

Roof pitches less than 4:12 are considered low-sloped roofs. Special installation practices must be used on roofs sloped 2:12 – 4:12. We offer residential roofing solutions in Aurora to cater to low slope roofs. 


A roof design with a nearly vertical roof plane that ties into a roof plane of less slope at its peak.


The general term for the base material of shingles and certain rolled products.

Modified Bitumen

Rolled roofing membrane with polymer modified asphalt and either polyester or fiberglass reinforcement.


Mixture of sand, mortar, limestone, and water, used in bonding a chimney’s bricks together.


Painted line on laminated shingles that aid in the proper placement of fasteners.


When a nail is not fully driven, it sits up off of the roof deck.


Installing a second layer of shingles aligning courses with the original roof to avoid shingle cupping.


The National Roofing Contractors Association. Respected national organization of roofing contractors.

Open Valley

Valley installation using metal down the valley center.

Organic Material

Material made from recycled wood pulp and paper.

Organic Shingles

Shingles made from paper products.


Orientated strand board. A decking made from wood chips and lamination glues.


The term used for fasteners driven through roofing material with too much force, breaking the material.


Installing shingle courses higher than their intended exposure.


Ratio of the rise of the roof to the span of the roof.

Plastic Cement

Asphalt-based sealant material, meeting ASTM D4586 Type I or II. Used to seal and adhere roofing materials. Also called MASTIC; BLACKJACK; ROOF TAR; and BULL.

Plumbing Vents

Term used to describe plumbing pipes that project through the roof.

Power Vent

Electrically-powered fans used to move air from attics and structures.

Prevailing Wind

The most common direction of wind for a particular region.

Quarter Sized

Term for the size of hand-sealant dabs; size of U.S. quarter.


Method of installing shingles in a straight-up-the-roof manner.

Rake Edge

The vertical edge of gable-style roof planes.

Roof Louvers

Rooftop rectangular-shaped roof vents. Also called BOX VENTS; MUSHROOM VENTS; AIRHAWKS; AND SOLDIER VENTS.

Roof Plane

A roofing area defined by having four separate edges. One side of a gable, hip, or mansard roof.

Self Sealant

Sealant installed on shingles. After installation, heat and sun will activate sealant. This is a popular choice for residential and commercial roofing solutions in Centennial, Colorado, and the entire Denver metro area.


The non-exposed area on rolled roofing. Areas without granules. Designed for nail replacement and sealant.

Shed Roof

Roof design of a single roof plane. Area does not tie into any other roofs.

Side Laps

The area on rolled material where one overlaps the rolled material beneath it. Also called selvage edge on rolled roofing.

Side Walls

Where a vertical roof plane meets a vertical wall, e.g. the sides of dormers.

Soffit Ventilation

Intake ventilation installed under the eaves, or at the roof edge.

Starter Strip

The first course of roofing installed. Usually trimmed from main roof material.

Steep-slope Roofing

Generally all slopes higher than 4:12 are considered steep slopes.


Metal flashing pieces installed at side walls and chimneys for weatherproofing.


The bottom portion of traditional shingle separated by the shingle cut-outs.


Removal of existing roofing materials down to the roof deck.


When shingles reflect the uneven surface beneath them. Shingles installed over buckled shingles may show some buckles.


When a roof plane ties into another roof plane that has a different pitch or slope.


Term used to describe a fastener not fully driven flush to the shingle’s surface.


Asphalt-based rolled materials designed to be installed under main roofing material, to serve as added protection.


Area where two adjoining sloped-roof planes intersect on a roof creating a V-shaped depression.


Term used to describe moisture-laden air.


Term used in roofing for the passage of air from an enclosed space.

Warm Wall

A finished wall inside of a structure. Used in roofing to determine how to install waterproof underlayments at eaves.


The written promise to the owner of roofing materials for material-related problems.

Waterproof Underlayments

Modified bitumen-based roofing underlayments. Designed to seal to wood decks and waterproof critical leak areas for both residential roofs and commercial roofs.

Woven Valleys

The method of installing valleys by laying one shingle over the other, up the valley center.

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