Roofing Glossary

At Affordable Roofing we think the more you know about your home’s roof, the more you will appreciate the professionalism we bring to every job.


Terms And Definitions Might Help You

The following list of terms and definitions might help you become a smarter roofing buyer.



Rooftop fungus that can leave dark stains on roofing.

Apron Flashing

Metal flashing used at chimney fronts.


A bituminous waterproofing agent used in various types of roofing 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, bull.

Back Surfacing

Granular material added to shingle’s back to assist in keeping separate during delivery and storage.


When shingles are subjected to high winds, and are forced off a roof deck.

Closed Cut Valley

A shingle valley installation method where one roof plane’s shingles completely cover the other’s. The top layer is cut to match the valley lines.


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


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

Drip Edge

An installed lip that keeps shingles up off the deck at edges, and extends shingles out over eaves and gutters.

End Laps

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.


Nails or staples used to secure roofing to the deck.

Fiberglass Mat

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


Materials used to waterproof a roof around any projections

Gable Roof

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


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

High Nailing

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

Hip Roof

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

“L” Flashing

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


The area where roll roofing or rolled underlayments overlap one another during application (see also side laps and end laps).


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

Modified bitumen

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

Nail Guide Line

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


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

Open Valley

Valley installation using metal down the valley center.

Organic Mat

Material made from recycled wood pulp and paper.


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


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

Rake Edge

The vertical edge of gable style roof planes.

Rigid Vent

Hard plastic ridge vent material.

Roof Louvers

Rooftop rectangular shaped roof vents. Also called box vents, mushroom vents, airhawks, soldier vents.


The exposed section of double thickness on shingles – also called dragon teeth. Shaped to imitate wood shake look on the roof.


The non exposed area on rolled roofing. Area without granules. Designed for nail placement and sealant.

Side Laps

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

Soffit Ventilation

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

Steep Slope Roofing

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


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


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


Term used to describe a fastener not fully driven flush to the shingles surface.


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

Waterproof Underlayments

Modified bitumen based roofing underlayments. Designed to seal to wood decks and waterproof critical leak areas.

Woven Valleys

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

Angled Fasteners

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


Asphalt Roofing Manufacturers Association. Organization of roofing manufacturers.

Asphalt Concrete Primer

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


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


Bubbles or pimples in roofing materials. Usually moisture related. In shingles blisters are caused by either moisture under the material or moisture trapped inside the material.


When a wrinkle or ripple affects shingles or their underlayments.

Counter Flashing

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


When shingles are improperly installed over an existing roof or are over-exposed, they may form a curl or cup. May also be due to a manufacturing defect.


A raised roof extending out of a larger roof plane.


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.


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


The Federal Housing Authority sets construction standards throughout the U.S.


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


When a wrinkle or ripple affects shingles or their underlayments.

Flashing Cement

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


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

Hip Legs

The down-slope ridges on hip roofs.

Ice Dam

Although not a frequent problem here in Florida, an ice dam occurs when a snow load melts on a roof and re-freezes at the eave areas. Ice dams force water to “back-up” under shingles and cause leakage.

Laminated Shingles

Shingles made from two separate pieces that are laminated together. Such as GAFMC Timberline® Series, Country Mansion® and Grand Sequoia® Shingles. Also called dimensional shingles and architectural shingles.

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. Shingles can not be installed at slopes less than 2/12.


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


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


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


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

Organic Shingles

Shingles made from organic (paper) mats.


Oriented Strand Board. A decking made from wood chips and lamination glues.


Installing shingle courses higher than their intended exposure.

Quarter Sized

Term for the size of hand sealant dabs, size of a U.S. 25¢ piece.

Roof Plane

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


Sealant installed on shingles. After installation, heat and sun will activate sealant to seal the shingles to each other.

Shed Roof

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

Side Walls

Where a vertical roof plane meets a vertical wall. The sides of dormers etc.

Starter Strip

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


Metal flashing pieces installed at sidewalls and chimneys for weatherproofing.


Removal of existing roofing materials down to the roof deck.


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


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.

Warm Wall

The finished wall inside of a structure, used in roofing to determine how far up the deck to install waterproof underlayments at eaves.


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