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Terms You Should Know
Deck/sheathing:
The surface, usually plywood or oriented strand board (OSB),
to which roofing materials are applied.
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Dormer: A small structure projecting
from a sloped roof, usually
with a window. |
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.
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Eave:
The horizontal lower edge of a sloped
roof. |
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.
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.
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Flashing: Pieces of metal used to
prevent the seepage of water around any
intersection or projection in a roof system,
such as vent pipes, chimneys, valleys and joints
at vertical walls. |
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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.
Penetrations:
Vents, pipes, stacks, chimneys–anything that penetrates
a roof deck.
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Rafters:
The supporting framing to which a roof deck is
attached. |
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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.
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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.
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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.
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