Pitched Roof Rafter Spacing

If your local building authority has a rafter spacing code you may not space rafters wider than required by code.

Pitched roof rafter spacing.

The same concept holds true for roof trusses. 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. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2. Rafters must be strong enough to hold the roof sheathing and the shingles.

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. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. For pitched roofs flat roofs and ceiling joists. So the space between rafters can be greater without reducing the maximum span.

Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings. Surveyors span tables for designing roof rafters. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches.