Roofing Glossary

Learning about roofs or finding out why your roof is leaking can be confusing! Here are common terms used in the roofing industry to help you stay on top of your roof!

Glossary of Roofing Terms

Algae

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 at chimney fronts.

ARMA

Asphalt Roofing Manufacturers Association. Organization of roofing manufacturers.

Asphalt

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

Asphalt Concrete Primer

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

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.

ASTM

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

Back Surfacing

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

Blistering

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.

Blow-Offs

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

Buckling

When a wrinkle or ripple affects shingles or their underlayments.

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.

Cobra^®

GAF’s respected brand name for ventilation products.

Counter Flashing

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

Country Mansion^®

GAF’s limited lifetime warranty shingle.

Crickets

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

Cupping

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.

Deck

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

Deck Armor

Deck Armor – premium breathable roof deck protection. It provides a critical extra layer of protection between your shingles and your roof deck to help prevent wind-driven rain (or water from other sources) from infiltrating under your shingles and causing damage to your roof structure or to the inside of your home.

Dormer

A raised roof extending out of a larger roof plane.

Drip Edge

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

Eaves

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.

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.

Exposure

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

Fasteners

Nails or staples used to secure roofing to the deck.

FHA

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

Fiberglass Mat

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

Flange

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

Flashing

Materials used to waterproof a roof around any projections

Flashing Cement

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

Gable Roof

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

GAFCant^®

GAF cant strips for deflecting water away from flashing areas. Typically used on low slope roofs.

Golden Pledge^®

GAF’s strongest limited warranty for shingles. America’s strongest steep slope warranty.

Grand Sequoia^®

GAF shingle with wood shake appearance.

Grand Slate

GAF shingle with slate appearance.

Granules

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

Hand-Sealing

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

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 eave areas. Ice dams force water to “back-up” under shingles and cause leakage.

“L” Flashing

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

Laminated Shingles

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

Laps

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

Liberty

Self-adhering low slope roofing. Liberty systems are applied without torches, open flames, hot asphalt, or messy solvent-based adhesives.

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.

Mansard

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

Mats

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.

Mortar

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

Nail Guide Line

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

Nail-Pop

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

Nesting

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

NRCA

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

Open Valley

Valley installation using metal down the valley center.

Organic Mat

Material made from recycled wood pulp and paper.

Organic Shingles

Shingles made from organic (paper) mats.

OSB

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

Overdriven

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

Overexposed

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.

Racking

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

Rake Edge

The vertical edge of gable style roof planes.

Release Film

The plastic sheet installed on the back of Weather Watch^® and StormGuard^®underlayments. Used for packaging and handling. Remove before installation.

Rigid Vent

Hard plastic ridge vent material.

Roof Louvers

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

Roof Plane

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

Sawteeth

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

Self-Sealant

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

Selvage

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

Shed Roof

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

Shingle-Mate^®

GAF’s shingle underlayment. Breather type with fiberglass backing to reduce wrinkles and buckles.

Side Laps

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

Side Walls

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

Soffit Ventilation

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

Smart Choice^® Limited Warranty

GAFMC’s standard shingle limited warranty.

Smart Choice^® System
Plus Limited Warranty

GAF’s next grade of enhanced warranty. Extended coverage for owners.

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.

Stepflashing

Metal flashing pieces installed at sidewalls and chimneys for weatherproofing.

StormGuard^®

GAFMC waterproof underlayment. Film surfaced rolled underlayment, 1.5 squares coverage per roll.

Tab

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

Tear-Off

Removal of existing roofing materials down to the roof deck.

Telegraphing

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

Timberline^® Series

GAF’s trademark name for laminated wood shake style shingles.

TIMBERTEX^®

GAF enhanced Hip and Ridge Shingles.

Transitions

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

Underdriven

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

Underlayments

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

Valleys

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

Vapor

Term used to describe moisture laden air.

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.

Warranty

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.

Weather Stopper^® Integrated Roofing System

GAF’s complete roofing system and components.

WeatherWatch^®

GAF’s granule surfaced waterproof underlayment.

Woven Valleys

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

** information from GAF.com