Roof Rafter Spacing

Rafter span tables use these two tables for roof rafters with a slope of 3 in 12 or less.

Roof rafter spacing.

Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes. Rafter spacing is based on the width of the metal roofing panels. Since most sheets are 4 x8 typical rafter spacing are 12 16 24. It is always better to have a large rafter rather than be concerned with a sagging roof.

A metal roof must also allow for some overlap on each side of the panels which will reduce the effective width of the panel. Wider panels allow for greater spacing between rafters. The same concept holds true for roof trusses. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.

Rafter spacing rafters must be strong enough to hold the roof sheathing and the shingles. If your local building authority has a rafter spacing code you may not space rafters wider than required by code. So the space between rafters can be greater without reducing the maximum span. In the us they are typically spaced at fractions of the roof sheathing size.

Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches. Use these two tables for roof rafters with a slope greater than 3 in 12.