Roofing Terms & Definitions
Asphalt: A bituminous waterproofing agent applied to roofing materials during manufacturing.
Back Surfacing: Fine mineral matter applied to the
backside of shingles to keep them from
sticking.
Blisters: Bubbles that may appear on the surface of asphalt roofing after installation.
Built-up roof: A flat or low-sloped roof consisting of multiple layers of asphalt and ply sheets.
Caulk: To fill a joint with mastic or asphalt cement to prevent leaks.
Class "A": The highest fire-resistance
rating for roofing as per ASTM E-108. Indicates roofing
is able to withstand severe exposure to fire originating from sources
outside the building.
Class "B": Fire-resistance rating that
indicates roofing materials are able to withstand moderate
exposure to fire originating from sources outside the building.
Class "C": Fire-resistance rating that
indicates roofing materials are able to withstand light
exposure to fire originating from sources outside the building.
Concealed nail method: Application of rolled roofing
in which all nails are driven into the
underlying course of roofing and covered by a cemented, overlapping course. Nails
are not
exposed to the weather.
Condensation: The change of water from vapor to
liquid when warm, moisture-laden air comes
in contact with a cold surface.
Coverage: Amount of weather protection provided by the roofing material.
Deck/sheathing: The surface, usually plywood or oriented
strand board (OSB), to which roofing materials are applied.
Dormer: A small structure projecting from a sloped
roof, usually with a window.
Downspout: A pipe for draining water from roof
gutters. Also called a leader.
Drip edge: An L-shaped strip (usually metal) installed
along roof edges to allow water run off to drip clear of the deck,
eaves and siding.
Eave: The horizontal lower edge of a sloped roof.
Edging Strips: Boards nailed along eaves and
rakes after cutting back existing wood shingles to provide secure edges
for re-roofing with asphalt shingles.
Fascia: A flat board, band or face located at a cornice's
outer edge.
Felt/underlayment: A sheet of asphalt-saturated material
(often called tar paper) used as a secondary layer of protection for
the roof deck.
Flashing: 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.
Fire rating: System for classifying the fire resistances
of various materials. Roofing materials are rated Class A, B or C,
with Class A materials having the highest resistance to fire originating
outside the structure.
Gable: The upper portion of a sidewall that
comes to a triangular point at the ridge of a sloping roof.
Granules: Ceramic-coated colored crushed rock
that is applied to the exposed surface of asphalt roofing products.
Gutter: The trough that channels water from
the eaves to the downspouts.
Insulation:A rigid board of various widths from 1/2 "to
6",
usually applied with some form of mechanical fasteners. When more than
one layer is applied the second layer will be applied with an adhesive,
either hot or cold.
Interlocking shingles: Individual shingles that
mechanically fasten to each other to provide wind resistance.
Louvers: Slatted devices installed in a gable or soffit
(the underside of eaves) to ventilate the space below a roof deck and
equalize air temperature and moisture.
Oriented strand board (OSB): Roof deck panels (4 by
8 feet) made of narrow bits of wood, installed lengthwise and crosswise
in layers, and held together with a resin glue. OSB often is used as
a substitute for plywood sheets.
Overhang: That portion of the roof structure
that extends beyond the exterior walls of a building.
Penetrations: Vents, pipes, stacks, chimneys-anything
that penetrates a roof deck.
Pitch: The degree of roof incline expressed
as the ratio of the rise, in feet, to the span, in feet.
Rafters: The supporting framing to which a roof deck
is attached.
Rake: The inclined edge of a roof over a wall.
Ridge: The top edge of two intersecting sloping roof
surfaces.
Sheathing: The boards or sheet materials that are
fastened to rafters to cover a house or building.
Soffit: The finished underside of the eaves.
Slope: Measured by rise in inches for each 12 inches
of horizontal run: A roof with a 4-in-12 slope rises 4 inches for every
foot of horizontal distance.
Square: The common measurement for roof area. One
square is 100 square feet (10 by 10 feet).
Truss: Engineered components that supplement rafters
in many newer homes and buildings. Trusses are designed for specific
applications and cannot be cut or altered.
Underlayment: A layer of asphalt saturated (sometimes
referred to as tar paper) which is laid down on a bare deck before
shingles are installed to provide additional protection for the deck.
Valley: The angle formed at the intersection of two
sloping roof surfaces.
Vapor retarder: A material designed to restrict the
passage of water vapor through a roof
system or wall.
Vent:. Any device installed on the roof, gable or soffitt for the purpose of ventilating the underside of the roof deck.