Roofing Parts and Terminology

Roofing Parts and Terminology

Built-up Roof

A low-slope (or flat-seeming) roof covered with alternating layers of roofing felt and hot-mapped asphalt and topped off with a layer of gravel.


The portion of the roof projecting out from the side walls of the house.


The flashing which is imbedded at its top in a wall or other vertical structure and is lapped down over shingle flashing.


Horizontal rows of shingles or tiles.


The surface, usually plywood or oriented strand board (OSB), to which roofing materials are applied.


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.


The lower edge of a roof (usually overhanging beyond the edge of the house).


Trimboard behind the gutter and eaves.


The “tar paper” used by roofer, usually made of a combination of asphalt and either paper or rags.

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.


Sheet metal or other material used at junctions of different planes on a roof to prevent leakage.

Frieze Board

A Board at the top of the house’s siding, forming a corner with the soffit.


The triangular upper part of a wall closing the end of a ridged roof.


The external angle at the junction of two sides of a roof whose supporting walls adjoin.


In a flat roof, a horizontal structural member over which sheathing is nailed.


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.


Vents, pipes, stacks, chimneys-anything that penetrates a roof deck.


A structural member (usually slanted) to which sheathing is nailed.


The slanting edge of a gabled roof extending beyond the end wall of the house.


The horizontal line at the top edge of two sloping roof planes.


The rigid material (often on inch by six inch or one inch by 12 inch boards or sheets of plywood) which is nailed to the rafters, and to which shingles or other outside roofing materials are secured.

Shingle Flashing

Flashing that is laid in strips under each shingle and bent up the edge of a chimney or wall.


The number of inched of vertical rise in a roof per 12 inches of horizontal distance. Also referred to as pitch.


The boards that enclose the underside of that portion of the roof which extends out beyond the sidewalls of the house.


One hundred square feet of roof, or the amount of roofing material needed to cover 100 square feet when properly applied.


Engineered components that supplement rafters in many newer homes and buildings. Trusses are designed for specific applications and cannot be cut or altered.


The material (usually roofing felt) laid on top of sheathing before shingles are applied.


The less-than 180-degree angle where two sloping roof sections come together.

Valley Flashing

The flashing in valleys, extending in under to shingles on both sides.

Vapor Retarder

A material designed to restrict the passage of water vapor through a roof system or wall.

Author: Paul Kleinmeulman

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