Roof Rafter Sizes And Spans

The lengths and sizes of joists vary depending on the species and quality of the lumber used.

Roof rafter sizes and spans.

Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. 2 are indicated below. L 720 l 600 l 480 l 360 l 240 l 180. 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.

More roof calculators roof truss calculator how to cut rafters. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. This calculator is to be used as an estimating tool only. Rafter stock size calculator.

Use these two tables for roof rafters with a slope greater than 3 in 12. Input the rafter span on the flat eave overhang and pitch of the roof. 3 stud construction standard utility. Live load 20 lbs ft 2 956 n m 2.

Floor joists ceiling joists rafters snow load rafters roof live load deflection limit. Rafter and joist span faq. Use these two tables for roof rafters with a slope of 3 in 12 or less. Area span on the flat.

Spacing in 12 16 19 2 24. For additional species of lumber check out the rafter span calculator from the american wood council website. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. For roof live loads less than 20 pounds per square foot psf rafter spans and required e values tabulated for 20 psf shall be permitted to be adjusted in accordance with the fol lowing table.

1 psf lb f ft 2 47 88 n m 2. The loads are based on adjusted roof snow loads from the governing building code. It is always better to have a large rafter rather than be concerned with a sagging roof. The above spans are based on american softwood lumber standard sizes.

Dead load weight of structure and fixed loads 15 lbs ft 2. Live load is weight of furniture wind snow and more. Rafter stock size calculator. This is based upon the span of the rafter horizontal span not total rafter length live and dead loads.

To size joists and rafters use the maximum span tables for southern yellow pine. 1 in 25 4 mm. 1 ft 0 3048 m. 2x4 2x6 2x8 2x10 2x12.

This calculator is to be used as an estimating tool only. An essential part of planning a patio roof or gazebo project is determining the number size and spacing of rafters beams and posts according to the loads they will carry. Input the rafter span on the flat eave overhang and pitch of the roof. This rafter span calculator is species specific for douglas fir hemlock etc.

Rafter spans are tabulated for the most common roof loads.