The structural "skin" of a roof over which roofing in applied. Most new homes have decking made of plywood. There are four main types of decking commonly used on residential roofing projects:

• Plywood: Plywood is strong, durable, and light. It comes in many grades with ratings from A to D. Use only exterior grade plywood for decking. The thickness of plywood depends on the spacing of the rafters.
• OSB: Oriented strand board (OSB) is cheaper than plywood, but not as strong as plywood, and does not hold nails as well as plywood. One side has a slip resistant coating and should be placed facing up.
• Tongue and groove 2-by-6: If a roof will be seen from the inside (no ceiling installed), tongue and groove is used. It is a wood decking that provides great insulation without additional rigid roof insulation in moderate climates. Also, the boards can be painted or stained on the inside to match the interior.
• Step sheathing: Step sheathing is used alone or in combinations with solid sheathing for installation of tiles or shakes. Step sheathing allows air circulations under the tiles by using 1-by-6 or 2-by-6 boards that are evenly spaced so that air can move under the tiles or shakes.

a shingle that is textured, overlayed, or laminated and designed to produce a three-dimensional effect. Similar to Laminated shingle and Architectural shingle.

A framed window unit that projects through the sloping plane of a roof.

Application of asphalt roofing such that the lapped portion is at least two inches wider than the exposed portion, resulting in two layers of roofing material over the deck.

A pipe for draining water from roof gutters. A downspout is also called a leader.

A non-corrosive, non-staining material used along the eaves and rakes to allow water run-off to drip clear of underlying construction.

a shingle that is textured, overlayed, or laminated and designed to produce a three-dimensional effect. Similar to Laminated shingle and Architectural shingle.