Our Glossary of Terms

Workers Building New RoofingsAt Douglas Roofing Co., Inc., we are committed to educating our clients. If you want to learn more about your roof and the roofing industry, then check out our glossary of terms.

We want to help you feel confident that you know all that you need to about our company and about one of the most important features of your home or business: the roof.

Glossary of Roof Terms:

Airborne Algae: Rooftop fungus that leaves dark stains or streaking on roofing.

Apron flashing: Metal flashing used at chimney fronts.

Asphalt: A bituminous waterproofing against used in various types of roofing materials.

Blistering: Bubbles or pimples in roofing materials, Usually relates to moisture trapped in or under roofing materials.

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

Buckling: When a wrinkle or ripple affects shingles and the underlayments.

CDX plywood:  C and D represent the quality of surfaces on front and back of the sheet. The X is for the exposure and indicates the type of glue used in the factory to bond the plywood veneers together, allowing it to withstand moisture for a short period of time.

Counter flashing: Metal or siding materials installed over roof flashing system.

Cricket: A peaked water diverter installed behind chimney.

Curling: When asphalt shingles begins to shrink overtime.

Deck: The substrate over which roofing is applied. This is usually plywood or sheathing.

Dormer: A raised roof extending out of a larger roof plane.

Drip edge: A metal lip that keeps the shingles off the deck at edges and extends the shingles over the eave and gutters. This will help prevent water and ice from entering the eave area.

Eaves: The edge of the roof near the gutters. The area extends up approximately 3ft.

Fasteners: Nails used to secure the roof to the deck.

Flange: Metal pan extended up or down the roof and around flashing, chimney or vents.

Flashing: Metal used to waterproof around any penetrations on roof.

FRT plywood: This Fire retardant treated plywood is used at the roof line in situations where building codes require fire-separation walls between dwelling units in townhouses, condominiums and apartments buildings.

Hip roof: A roof with four roof planes coming together at the peak and four separate legs.

Ice dam: When snow melts on a roof and re-freezes at the eave area. Ice dams force water back-up under shingles and cause leakage.

Mansard: Also called a French roof or curb roof, a roof design with a nearly vertical roof plane that ties into a roof plane of less slope at its peak.

Nail pops: When a nail sits up off the roof deck, sometimes lifting the shingle.

NRCA: The National Roofing Contractors Association.

Open valley: Metal is installed down the center of the valley.

OSB: Oriented Strand Board is made from wood chip and lamination glues.

Pitch: The slope of the roof.

Rake: The vertical edge of a roof plane.

Ridge: also called the peak or apex of the roof.

Ridge Vent: Hard plastic or metal vent system at the ridge.

Shingle: Outward layer of roofing materials made of asphalt and oils making them durable and waterproof.

Square: Roof shingles are figured by number of squares. 10’ x 10’ = 100sf (1 square)

Starter strip: the first course of roofing that is installed at the eave area.

Tear-off: Removal of existing roof materials to the roof deck.

Underlayments: Asphalt based rolled material installed over the roof deck, under main roof materials.

Valley: An area where two sloped roof planes intersects, creating a V shape.

Woven valley: Installing one shingles over the other in the valley to create a woven look.