Rafter Spacing For Tile Roof

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.

Rafter spacing for tile roof.

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. With rafters it runs in perpendicular from the walls to the ridge while with purlins it runs to the ridge in parallel. Use these two tables for roof rafters with a slope of 3 in 12 or less. Battens should be fixed to rafters set at centres not more than 600 mm apart and should span at least 3 rafters.

To ensure this the battens should be at least 1 2m long. So the space between rafters can be greater without reducing the maximum span. If your local building authority has a rafter spacing code you may not space rafters wider than required by code. The same concept holds true for roof trusses.

The support system for the roof is comprised of ridgepole and rafters or purlins. Using a combination of rafters and purlins is common. 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. It is also important aesthetically so that the tiles on the finished roof are equally spaced.

Rafter spacing rafters must be strong enough to hold the roof sheathing and the shingles.