Pitched Roof Rafter Spacing

Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches.

Pitched roof rafter spacing.

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. 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. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Rafters must be strong enough to hold the roof sheathing and the shingles.

So the space between rafters can be greater without reducing the maximum span. 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. 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. The same concept holds true for roof trusses.

If your local building authority has a rafter spacing code you may not space rafters wider than required by code. 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. For pitched roofs flat roofs and ceiling joists.