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Roofing Terminology
Roofing Terminology

Glossary of Roofing Terms 

Definitions of common roofing terms 


Cornice:  The overhang of the roof at the eaves line that forms a connection between the roof and the sidewalls.  

Deck/sheathing:  The flat, substructure surface, usually plywood or oriented strand board (OSB - see definition below), to which roofing materials are applied.

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 runoff to drip clear of the deck, eaves, and siding. 

Eave:  The overhanging lower edge of a 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. Its purpose is to waterproof roofs to prevent moisture from reaching past the top of the roof deck. 

Fire rating:  System for classifying the fire resistance 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. 

Flashing:  Pieces of metal used to prevent the seepage of water around any intersection or projection in a roof system, such as joints at vertical walls, chimneys, vent pipes, and valleys. 

Louvers (vents):  Slatted devices installed in a gable or soffit to allow ventilation in the space below a roof deck and even out air temperature and moisture. 

Oriented strand board (OSB or waferboard):  Roof deck panels (4 by 8 feet) made of narrow bits of wood, installed lengthwise and crosswise in layers, and held together with resin glue. OSB often is used as a substitute for plywood sheets. 

Penetrations:  Anything that penetrates a roof deck, such as vents, pipes, stacks, and chimneys. 

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. 

Slope/Pitch:  Measured by rise in inches for each 12 inches of horizontal run: A roof with an 8-12 slope rises 8 inches for every foot of horizontal distance.

Soffit:  The underside area of the overhang of the roof.  

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. 

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.

If you have any questions or would like us to add a specific definition, please contact us!



Craft Roofing
402A W. Palm Valley, #156, Round Rock, TX 78664
512.244.7926 -- Fax 254.793.2771



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