Comprehensive Roofing Terms and Definitions

Algae Resistance: Ability of roofing materials to resist algae growth, often through special treatments or coatings.

Alligatoring: A pattern of cracks on the surface of aged asphalt roofing that looks similar to alligator skin.

Asphalt Shingles: Durable, cost-effective roofing material made from fiberglass and asphalt, topped with mineral granules. Commonly used in residential roofs.

Back Surfacing: Fine mineral matter applied to the back side of shingles to keep them from sticking together.

Bitumen: Mixture of hydrocarbons from petroleum, used in roofing materials.

Blistering: Bubbles in roofing material caused by trapped moisture or poor installation.

Blow-Offs: When shingles or other roofing materials are torn away from the roof deck by high winds.

Bridging: A method of reroofing with less efficient materials.

Built-Up Roof: A flat roof made of multiple layers of asphalt and ply sheets, known for durability.

Caulking: Material used to seal joints or seams 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.

Chimney Cap: A cover at the top of a chimney to prevent rain, debris, and animals from entering.

Coating: A layer of liquid material applied to a roof membrane for protection.

Cool Roof: A roof designed to reflect more sunlight and absorb less heat, improving energy efficiency.

Counter Flashing: Flashing installed opposite or above another flashing to shed water.

Course: A row of shingles or tiles on a roof.

Coverage: The amount of weather protection provided by the roofing material.

Cupola: A small dome or tower on a roof, often for ventilation or decoration.

Curling: When shingle edges curl upwards or downwards, often due to weathering or poor ventilation.

Dead Level: A roof with no pitch.

Deck: The structural surface to which roofing is applied.

Dormer: A window that projects vertically from a sloping roof, adding light and space toan attic.

Drip Edge: Metal flashing at the roof edge that directs water into the gutters, protectingthe fascia.

EPDM (Ethylene Propylene Diene Monomer): Durable synthetic rubber roofing membrane for flat roofs.

Eave: The part of the roof that extends beyond the exterior wall, providing an over hang.

Fascia: The vertical edge under the roof’s overhang that supports the lower edge of the roof and gutters.

Fasteners: Nails or staples used to secure roofing to the deck.

Felt: Fibrous material saturated with asphalt and used as an underlayment between the roof deck and the roofing material.

Flange: Metal edges of a roof penetration flashing.

Flashing: Thin metal sheets installed around roof features (like chimneys and vents) top revent water from seeping into the structure.

Gable: The triangular section of an exterior wall between the slopes of a roof.

Gambrel Roof: A type of roof with two slopes on each side, the lower slope having a steeper pitch.

Granules: Small ceramic-coated stones on asphalt shingles that protect against UV rays and add color.

Granule Loss: Wearing away of granules from asphalt shingles, typically due to aging or weathering.

Green Roof: A roof partially or completely covered with vegetation, offering environmental benefits and insulation.

Gutter: Horizontal trough installed along the eaves to catch and carry off rainwater.

Heat Tape: Electrically powered tape used to prevent ice dams by warming the edge of the roof.

Hip Roof: A roof with slopes on all four sides, providing extra stability and a unique aesthetic.

Ice Dam: A build-up of ice along the roof edge that prevents melting snow from draining, potentially causing leaks.

Impact Resistance: Ability of roofing materials to withstand impacts from hail or debris without damage.

Inspection: The process of examining the condition of the roofing system.

Interlocking Shingles: Shingles that lock together to provide better wind resistance.

Joist: A horizontal structural member over which sheathing is nailed.

Kickout Flashing: Flashing that directs water away from the wall and into the gutter system.

Laminated Shingles: Shingles that have added dimensionality because of extra layers or tabs.

Liquid-Applied Roofing: Roofing materials applied in liquid form, which harden to create a seamless membrane.

Loose Laid: A method of installing roofing material without securing it to the deck.

Modified Bitumen: Asphalt-based roofing with added polymers for flexibility, used on flat or low-sloped roofs.

Moisture Relief Vent: A vent installed to allow moisture to escape.

Overlay: Installing a new roof system over an existing one.

Overdriven Nail: A nail driven too far into the roofing material, potentially causing damage or reducing effectiveness.

Patching: Minor repairs to damaged areas of the roofing system.

Penetrations: Vents, pipes, stacks, chimneys, or other objects that pierce the roof deck.

Pipe Collar: A ring around a vent pipe at the roofline to prevent water penetration.

Pitch: The steepness of a roof, expressed as a ratio of vertical rise to horizontal run.

Ply: A layer of roofing material.

Polymer: A substance made of many repeating chemical units or molecules. Used in roofing materials to increase durability and weather resistance.

R-Value: A measure of thermal resistance. Higher R-values indicate better insulating properties.

Rafters: Sloped beams supporting the roof deck and materials.

Reflectivity: The ability of a material to reflect solar heat.

Re-Roofing: Installing a new roof system on a building that is already roofed.

Ridge Cap: Shingles or tiles covering the roof ridge, providing a finished look and added protection.

Ridge Vent: Ventilation system placed along the roof’s peak to allow hot, humid air to escape from the attic, improving energy efficiency.

Roof Assembly: The combination of roof components including deck, insulation, membrane or primary roof covering, and accessories.

Roof Deck: The base layer of the roof, typically made of plywood or OSB, to which roofing materials are applied.

Roof Slope: The angle of the roof surface.

Roof System: The combination of all the components that make up the roof, including the deck, underlayment, shingles, and ventilation.

Roof Truss: A structural framework of rafters, posts, and struts supporting the roof.

Roofing Felt: Heavy paper soaked in asphalt, used as an underlayment beneath shingles.

Saddle: A small structure that diverts water around the high side of a chimney or other roof penetration.

Soffit: The underside of the roof overhang, aiding in attic ventilation and protecting rafters from weather.

Square: Unit of measure for roofing materials, equal to 100 square feet.

Starter Strip: The first row of shingles along the eave, providing a base for the first course of shingles.

Step Flashing: Flashing pieces that are layered with roofing shingles to prevent water from entering at roof-to-wall intersections.

Tab: The portion of an asphalt shingle that is exposed to the weather after installation.

Tear-Off: The process of removing an existing roof system.

Three-Tab Shingles: Asphalt shingles with three tabs, giving a uniform appearance.

Tile Roof: Roofing made from clay or concrete tiles, known for durability and aesthetic appeal.

Torch Down: Method of installing roofing membranes by heating with a torch to adhere them to the roof surface.

Underlayment: Protective layer installed between the roof deck and shingles, providing extra water resistance and preventing leaks.

Valley: The V-shaped intersection of two sloping roof sections, designed to channel water off the roof.

Vapor Barrier: A material designed to prevent moisture from passing through walls or roofs.

Vent: An opening that allows air to circulate through the attic or roof deck.

Ventilation Baffle: Device ensuring proper airflow in the attic, preventing insulation from blocking ventilation paths.

Vent Pipe: A pipe extending through the roof to ventilate plumbing systems, sealed with a flashing boot to prevent leaks.

Woven Valley: Method of valley construction where shingles from both sides are alternated, providing a continuous line of shingles through the valley