Roof Rafter Spacing

If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.

Roof rafter spacing.

Since most sheets are 4 x8 typical rafter spacing are 12 16 24. Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes. It is always better to have a large rafter rather than be concerned with a sagging roof. Wider panels allow for greater spacing between rafters.

Rafter span tables use these two tables for roof rafters with a slope of 3 in 12 or less. A metal roof must also allow for some overlap on each side of the panels which will reduce the effective width of the panel. In the us they are typically spaced at fractions of the roof sheathing size. If your local building authority has a rafter spacing code you may not space rafters wider than required by code.

Use these two tables for roof rafters with a slope greater than 3 in 12. So the space between rafters can be greater without reducing the maximum span. The same concept holds true for roof trusses. The above spans are based on american softwood lumber standard sizes.

In california 16 is by far the most common for residential construction. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches.