Glossary of Roofing Terms
Asbestos – A naturally occurring mineral fiber which is resistant to high temperature. Less used today because of the harmful effect of the fibers.
Asphalt – End product of petroleum distillation process; it is the waterproofing and adhesive component of a built up roof. It is commonly available in three grades: Dead Level, Flat, and Steep. The grade is determined by its melting point.
A.S.T.M. – American Society for Testing Materials. An organization that sets standards for a wide variety of materials, including roofing.
Boston - style hip and ridge –A method of covering hips and ridges with overlapping materials and hidden fasteners.
Built-up Roofing – Roof membrane composed of multiple layers, or plies, of asphalt felt constructed with inter-ply moppings of asphalt. Most common are a three or four ply built-up roof.
Cant Strip – 4 x 4 or 6 x 6 piece of wood cut diagonally (corner to corner) to form one face with a 45-degree angle. Used at eaves and walls to create a gradual transition from horizontal to vertical.
Clay Tile – A roofing tile made from hard, baked clay.
Coal Tar Pitch – End product of coal coking process. Used like asphalt, but used with coal tar pitch saturated felts. Much more durable than asphalt.
Condensation – The change from a gaseous state to liquid state as temperature drops or atmospheric pressure rises.
Conductor Box – A box, often decorative, designed to collect and divert water down into a downspout, also, referred to as a leader head or scupper.
Coping – The top component of a parapet wall, it acts to seal the top of the wall; usually fabricated from metal, clay, or concrete.
Counter-flashing – Secondary flashing overlapping the base flashings
Cricket – A peaked water diverter installed behind chimneys and other large roof projections. Effectively diverts water around projections.
Deck - The substrate over which roofing is applied. Usually plywood, wood, boards, or planks.
Delamination – Separation of plies in a roofing membrane of plywood.
Dew Point – The temperature at which a vapor begins to condense.
Dormer – A vertical window unit projecting through the sloping plane of a roof.
Drip Edge Metal (T-style) – An installed lip that keeps shingles up off the deck at edges and extends shingles out over eaves and gutters, and prevents water from backing up under shingles. (Also referred to as D-style.)
Eaves – Horizontal edge of the roof.
EPDM – Ethylene Propylene Diene Monomer synthetic rubber compound developed for used as a roofing membrane.
Exposure – The area on any roofing material that is left exposed to the elements.
Faзade – The face of a building, usually the front.
Fascia – A horizontal band of vertical facing material usually below the edge of the roof.
Felt – Asphalt based rolled materials designed to be installed under main roofing material, to serve as added protection.
Field – The area covered by roofing material.
Finial – A decorative point that finishes off the top of an architectural detail, as on a spire.
Fish mouth – An edge wrinkle forming a half-conical opening.
Flashing – Materials used to waterproof a roof around any projections through the roof deck or at the edge of the roofing system.
Gable – The triangle ends of a building under a gable roof.
Gambrel – A double pitched roof, which terminates in a small gable at the ridge and where the angle of pitch is abruptly changed between the ridge and eave. (Barn style)
Granule – Artificially colored particles of siliceous material used on composition roofing.
Gutter Apron Metal – A special style of drip edge that is used with gutters having no roof flange.
Hip Roof – A roof, which slopes upward from all four sides.
Ice Dam – When a snow load melts on a roof and re-freezes at the eave areas. Ice dams force water to “back-up” a roof and cause leakage.
Ice and Water Shield – Self adhering rubberized asphalt sheet membrane designed to prevent moisture, caused by ice back-up, from entering the building. To be effective this sheet must be place directly on the roof sheathing.
Impact Resistance – The ability of a layer of asphalt to resist cracking or breaking when the material on which it is applied receives a hard blow or knock.
Live Load – The total weight of all installed equipment, materials and all variable weight (such as snow, ice, and people) that will move across a surface.
Mansard Roof – A roof design with a nearly vertical roof plane that ties into a roof plane of less slope or a flat roof.
Modified Bitumen – A roofing bitumen which generally has been mixed with rubber or plastic compounds to provide greater elasticity, flexibility and improved working characteristics.
Parapet – A low, retaining wall at the edge of a roof.
Pitch – Ratio of the rise of the roof to the span of the roof. Usually referred to by a number, i.e. 6 pitch, which refers to the vertical rise in inches for every 12 inches of horizontal distance. The higher the number the steeper the slope.
Plumbing vent jackets (jacks) – The metal covering for plumbing vents, which can be flashed into the roof.
Ply – A single layer of organic or inorganic roofing material in a roof membrane system.
Ponding – Water sitting on a roof system for a period of time.
Rafter – A supporting member immediately beneath the roof sloping from the wall plate to the ridge.
Rake – The edge of a roof at the gable end.
Reglet – A small groove cut into the side of a masonry wall for inserting the counter-flashing.
Relative Humidity – The ratio of the amount of water vapor actually present in the air to the greatest amount possible at the same temperature.
Ridge – The high point where two sloped roofs meet. Also called the peak.
Roof Louvers – Rooftop rectangular shaped vents for exhausting air from the attic space.
Saddle – Metal or rubber flashing set at a high side of rectangular roof proje
ctions such as chimneys or skylights to divert water around the projections.
Shed Roof – A roof having only one sloping plane. Area does not tie into any other roofs.
Shingle Tins – a step flashing installed at sidewalls, skylights, or chimneys where they meet the end of a course of shingles, in effect extending the course up the sidewall.
Slate – A hard, naturally occurring material, similar to stone, that splits easily into thin sheets. Used for roofing and flooring.
Slope – The degree on inclination of a roof plane or inches of rise per horizontal foot. (See Pitch)
Soffit – The finished underside of an eave.
Square – An area of roofing 10 feet x 10 feet. (100 sq. feet)
Starter course – The first course of roofing installed. Usually trimmed from main roofing material, but may be in rolls or in pre-cut bundles.
Step Flashing – Metal-flashing pieces installed at sidewalls, skylights, and chimneys.
Valleys – Area where two adjoining sloped roof planes intersect on a roof creating a “V” shaped depression.
Vent – An outlet of air; vent pipe in a plumbing system; a ventilating outlet.
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