Typical Roof Rafter Spacing

In the us they are typically spaced at fractions of the roof sheathing size.

Typical roof rafter spacing.

Spans for joists greater than 20 feet that are parallel to the rafters require a 12 inch joist spacing when using 2 inch by 10 inch 2 douglas and hemlock fir or southern pine or 16 inch spacing when using 2 inch by 10 inch 2 douglas fir or southern pine. This is the distance between rafter centres. Rafter span tables use these two tables for roof rafters with a slope of 3 in 12 or less. Rafter spacing depends on the roofing panel size.

But they do tend to space rafters in one of several industry standard increments typically either 12 16 or 24 inches apart. Since most sheets are 4 x8 typical rafter spacing are 12 16 24. It will support roof loads for most situations and is the standard for most roof applications. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.

The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that. The above spans are based on american softwood lumber standard sizes. Usually 400 450 or 600mm but any value can be used up to 610mm max are there any brittle finishes e g. Builders aren t bound by standard rafter spacing measurements.

Use these two tables for roof rafters with a slope greater than 3 in 12. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches. Plasterboard on the underside of the rafter. Stockbyte stockbyte getty images when placing rafters for a tin roof also frequently referred to as corrugated metal or steel it is common to set the distance between rafters based on the size of the roofing panels.

There is no standard spacing it depends on what size of rafters you want to use and the span of your shed. For instance 2 grade 2x4s at 16 on center will span just over 9. It is always better to have a large rafter rather than be concerned with a sagging roof.