What Size Lumber For Roof Rafters

Use these two tables for roof rafters with a slope greater than 3 in 12.

What size lumber for roof rafters.

If you look at the rafter span chart you ll notice that 2x4s can be used for rafters on spans up to 11. For roofs that won t experience heavy snow loads a gable roof can span up to 22 with 2 4 rafters. More roof calculators roof truss calculator. Once all of these inputs have been entered into the calculator you will see that the appropriate rafter width is 120 33 inches.

This rafter span calculator is species specific for douglas fir hemlock etc. Trying to find what size lumber to use. Just enter the dimensions of the roof rise and run to get started. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.

To size joists and rafters use the maximum span tables for southern yellow pine. Use these two tables for roof rafters with a slope of 3 in 12 or less. For example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine. 1 psf lb f ft 2 47 88 n m 2.

In addition using the rafters diagram you can see the precise dimensions of the roof rafter including length from every possible angle. 1 ft 0 3048 m. You can use either 2 6 or 2 4 rafters for roofs with a 3 12 pitch or greater but it depends on the overall size of your shed. This calculator helps you make the rafters of the suitable sizes required for your roofing.

This is based upon the span of the rafter horizontal span not total rafter length live and dead loads. Here the wall thickness is 240 57 inches. If you re building rafters and aren t sure where to start when determining the length of your lumber you re in the right place our rafter stock size calculator shows you how long your rafters should be so you ll know what you need in terms of framing lumber dimensional lumber studs and more. Rafter is a sloping beam usually wood that supports a pitched roof.

Dead load weight of structure and fixed loads 15 lbs ft 2. 2 are indicated below. The pitch and span of your roof will dictate how long of a rafter you ll need use maximum span calculator to help you find your rafter size. Anything beyond that you are looking at using 2x6s for most sheds.

The above spans are based on american softwood lumber standard sizes. For roofs that will experience heavy snow or wind and will span the same distance use 2 6 rafters. Rafter and joist span faq. For additional species of lumber check out the rafter span calculator from the american wood council website.

If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Live load is weight of furniture wind snow and more.