Roofing From A to Z

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 A  |  B |  C  | D |  E  | F |  G  |  H  |  I  |  J  |  K  |  L  |  M  |  N  |  O  |  P  |  R  |  S  |  T  |  U  |  V  |  W 

Algae Rooftop fungus that can leave dark stains on roofing.

Apron Flashing – Metal flashing used at chimney fronts.

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.

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

Base Sheet – An asphalt-impregnated, or coated felt used as the first ply in some built-up and modified bitumen roof systems.

Blistering – Bubbles in roofing materials.  Usually moisture related.  In shingles, blisters are either moisture under the materials or moisture trapped inside the material.

Buckling – When a wrinkle or ripple affects shingles or their underlayment.

Bundle – a package of shingles – there are 3, 4, and 5 bundles per square.

Cap Sheet – A granule-surfaced membrane often used as the top ply of BUR or modified roof systems.

Caulk – To fill a joint with mastic or asphalt cement to prevent leaks.

Cement – See asphalt plastic cement

Closed-Cut-Valley – A shingle valley installation method where one roof plane’s shingles completely cover the others.  The top layer is cut to match the valley lines.

Coping – The piece of material used to cover the top of a wall and protect it from the elements.  It can be constructed from metal, masonry, or stone.

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

Counter-Flashing – The metal or siding material that is installed over rooftop base flashing systems.

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

Coverage – 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 (i.e. – single coverage, double cover, etc.).

Crickets – a peaked water diverter installed behind chimneys and other large roof projections.  Effectively diverts water around projections.

Cupola – A relatively small roofed structure set on the ridge of a main roof area – also known as a Crow’s Nest.

Curb – A raised member used to support skylights, HVAC units, exhaust fans, hatches or other pieces of mechanical equipment above the level of the roof surface, and should be a minimum of eight inches in height.

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

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

Downspout – A pipe for draining water from roof gutters – also called a leader.

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

Dry-In – The process of installing the underlayment roll roofing, making a roof watertight.

Dry Rot – Wood rot caused by certain fungi.  Dry rot can result from condensation build-up, roof leaks that go untended, or from other problems.  Dry rot will not remain localized.  It can spread and damage any lumber touching the affected area.

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.

Eaves Flashing – Additional layer of roofing material applied to the eaves to help prevent damage from water backup.

Elastomer – A material which, after being stretched, will return to its original shape.

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 (i.e. – underlayments, rolled roofing).

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

Exposure / Grade Plywood – Type of plywood approved by the American Plywood Association for exterior use.

Fascia – Vertical roof trim located along the perimeter of a building, usually below the roof level.

Fasteners – 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.

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

Field – Refers to the central part of a roof away from the perimeter.

Flashing – Materials used to waterproof a roof around any projections through the roof deck.  Pieces of metal or roll roofing used to prevent seepage of water into a building around any intersection or projection in a roof such as vent pipes, chimneys, adjoining walls, dormers and valleys.  Galvanized metal flashing should be a minimum 26-gauge.

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

FM – Factory Mutual Research Corp.

Gable – The upper portion of a sidewall that comes to a triangular point at the ridge of a sloping roof.

Gable Roof – Traditional roof style – two-peaked roof planes meeting at a ridgeline of equal size.

Galvalume – Trade name for a protective coating composed of aluminum zinc.

Galvanize – To coat with zinc.

Granules – Crushed rock that is coated with a ceramic coating and fired, uses as to surface on shingles.

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

Hip – The inclined external angle formed by the intersection of two sloping roof planes.  Runs from the ridge to the eaves.

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.

Hip Shingles – Shingles used to cover the inclined external angle formed by the intersection of two sloping roof planes.

Insulation – Material used to help maintain a certain temperature in a building by reducing the flow of heat to and from that building.

“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 pieced that are laminated together – also called dimensional or architectural shingles.

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

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.

Mansard Roof – a roof design with a nearly vertical roof plane that ties into a roof plane of less-slope at its peak.

Membrane – The portion of the roofing system that serves as the waterproofing material.  Can be composed of one material or several materials laminated together.

Mineral-surfaced Roofing – Asphalt shingles and roll roofing that are covered with granules.

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

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

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

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

Over Exposed – Installing shingle course higher than their intended exposure.

Overhang – That portion of the roof structure that extends beyond the exterior walls of a building.

Penetration – Any object that pierces the surface of the roof.

Pitch – Ratio of the rise of the roof, in inches, to the span of the roof, in feet (i.e. – 4/12).

Power Vents – Electrically powered fans used to move air from attics and structures.

Plastic Cement – Asphalt based sealant, also called bull, mastic, tar and asphalt cement.

Plumbing Vents – Term used to describe plumbing pipes that project through a roof plane, also called vent stacks.


Ply – The number of layers of roofing (i.e. – one-ply, two-ply).

Ponding – The accumulation of water at low-lying areas on a roof.

Quick-setting Cement – An asphalt-based cement used to adhere tabs of strip shingles to the course below.  Also used to adhere roll roofing laps applies by the concealed nail method.

Rafter – The supporting framing member immediately beneath the deck, sloping from the ridge to the wall plate.

Rake Edge – The vertical edge of gable style roof planes.

Release Tape – A plastic or paper strip that is applies to the back of self-sealing shingles.  This strip prevents the shingles from sticking together in the bundles, and need not be removed for application.

Ridge – The uppermost, horizontal external angle formed by the intersection of two sloping roof planes.

Ridge Vent – Hard plastic ridge vent material.

Roll Roofing – Asphalt roofing products manufactured in roll form.

Saturated Felt – An asphalt-impregnated felt used as an underlayment between the deck and the roofing material.

Self-sealing Shingles – Shingles containing factory-applies strips or spots for self-sealing adhesive.

Shading – Slight differences in shingle color that may occur as a result of normal manufacturing operations.

Sheathing – Exterior grade boards used as a roof deck material.

Single Coverage – Asphalt roofing that provides one layer of roofing material over the deck.

Slope – The degree of roof incline expressed as the ratio of the rise, in inches, to the run, in feet.

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

Soil Stack – A vent pipe that penetrates the roof.

Square – A unit of roof measure covering 100 square feet.

Starter Strip – The first course of roofing installed, usually trimmed from main roof material.

Substrate – The surface that the roof is installed upon.

Tab – The bottom portion of traditional shingle separated by the shingle cutouts.

Tear-offs – Removal of existing roofing materials down to the roof deck.

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

Trivia Answer – The average size roof is 3500 Square Feet and will need 2205 shingles. Each shingle will need 6 nails, so…6 x 2205 = 13,230 nails. If using 4 nails per shingle the answer would be 8,820.  Have a question? Call Robert long at 239-872-2671

Transitions – When a roof plane ties into another roof plane that has a different pitch or slopes.

UL – Underwriters Laboratories Inc.

UL Label – Label displayed on packaging to indicate the level of fire and/or wind resistance of asphalt roofing.

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

Underlayments – Asphalt based rolled materials, which are 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.

Vent – Any outlet for air that protrudes through the roof deck such as a pipe or stack.  Any device installed on the roof, gable, or soffit for the purpose of ventilating the underside of the roof deck.

Ventilation – The term used in roofing for the passage of air from an enclosed space.

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

Waterproof Underlayments – Modified bitumen based roofing underlayments, which are designed to seal wood decks and waterproof critical leak areas.

Wind Load – The force that wind puts on structures.

Wind Uplift – the upward displacement of a section of a roof system or component caused by movement or air from a location of higher air pressure, to an area of lower air pressure.  Strong wind along the surface of a roof, especially at corners and along perimeters, creates low air pressure above the surface of the roof.  Displacement or blow-off of shingles or other roofing caused by the wind.

For any other terms or questions call Robert Long at 1-866-540-4550 or email me at: