How to Use Round Rafters

Rafters are the larger structural members at the top of a roof system. The rafter directly supports roof decking (sheathing) as builders complete construction. Rafters are typically made from 2-by-8 or 2-by-10-inch dimensional lumber when they are not manufactured in a pre-engineered truss. When building rustic log homes, contractors can use round profile trusses for exposed Cathedral ceilings. The round profile rafters give a rustic look to the home's interior. The top surface of the rafter should be milled flat to improve the stability of the roof decking.

Round profile rafters
7 1/4" builders saw
Saws-all, or reciprocating saw.
Measuring tape, pencil
Pocket bevel, or framing square
Builders framing nail gun, with air compressor.

Instructions

- 1
  Position the rafter so the flat surface of the rafter faces upward, toward the roof decking. Round rafters should have a flat surface that is between 3-4 inches wide, milled along one side.
- 2
  Miter the top end of the rafter with the builders saw or reciprocating saw so that the rafter meets the ridge board in a vertical joint. Two rafters will be directly adjacent from one another, and meet at the apex of the roof line at the ridge board which runs the length of the roof's peak.
- 3
  Miter or notch the bottom end of the rafter with the reciprocating saw so that a flat surface rests on top of the exterior wall. The rounded bottom surface of the rafter must be cut so it distributes the weight of the roof system on the exterior wall, and so that the rafter can be securely fastened to the wall. In most installations, the rafter is notched, and then continues to the exterior of the home. In some installations, the rafter ends at the exterior wall. In either case, the rounded rafter must be mitered and cut so that a flat surface on the rafter meets the flat surface of the wall plate.

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