Flat Roof Rafter Spacing

As a general rule roofs that have a high human occupancy rate should be framed with rafters every 16 structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes.

Flat roof rafter spacing.

The same concept holds true for roof trusses. The rafters in a flat roof serve as ceiling joists for the space below. Common spacing for trusses on this type of building is often between 2 and 4 feet but trusses built with advanced designs may allow spacing as great as 8 or 12 feet. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.

Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run. So the space between rafters can be greater without reducing the maximum span. 1 ft 0 3048 m. Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.

If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Live load is weight of furniture wind snow and more. They are nailed securely to exterior wall plates and to each other. 1 psf lb f ft 2 47 88 n m 2.

The size of rafters for a flat roof depends on the horizontal span of the building the type and grade of timber used and the load on the roof. 2 are indicated below.