Framing for a Roof Over a Wooden Deck

Design

• Picking a roof style is the first consideration. Even shed roofs, which slope in only one direction, involve some design considerations. A wood deck's roof can be freestanding or attached to the house. It can cover the entire deck or just part of it, leaving an open area such as an observation platform. It can be just a basic roof or include spaces for lights, fans or even heating vents.

Considerations

• Framing a wood deck's roof requires installing outer bands along the deck's perimeter with angled roof joists or rafters between the ends to support roofing. They usually are spaced 24 inches apart and cut to conform to the roof's slope. The roof should slope away from the house by at least 2 inches per foot and preferably more inches per foot. A 10-foot long deck roof, for instance, must be 20 inches higher on its house side than on its outside edge.

Basic Supports

• Using a house to support one end of the deck roof involves removing some siding or shingles and installing a ledger board fastened to the house to support deck roof rafters. Building a freestanding roof requires adding columns on the house side of the deck and leaves an opening between the deck and the house.

Outer Supports

• All deck roofs require support on their outer edge. The support may be posts sunk in the ground at the edge of the deck; that method requires digging deep post holes and setting them in concrete. Posts or columns also can be set on a wooden deck by using metal brackets, which are fastened to the deck with screws and have vertical sides to hold posts. Posts must be sturdy enough to support the roof frame's weight.

Roofing Material Choices

• The roofing material that will be used affects deck roof framing. Shingles to match the house are an ideal choice, but they require strong framing and solid roof decking. Decking such as oriented strand board (OSB) may require decorative finishing on the inside of the roof because basic OSB is not considered attractive. Substituting plywood decking may add expense to the project. Corrugated metal or vinyl is effective and simple to install but may not be as attractive as shingles.