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.
Roof rafter sizes and spans.
For additional species of lumber check out the rafter span calculator from the american wood council website.
This is based upon the span of the rafter horizontal span not total rafter length live and dead loads.
The above spans are based on american softwood lumber standard sizes.
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.
It is always better to have a large rafter rather than be concerned with a sagging roof.
This rafter span calculator is species specific for douglas fir hemlock etc.
Rafter stock size calculator.
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.
2x4 2x6 2x8 2x10 2x12.
Rafter spans are tabulated for the most common roof loads.
Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.
This calculator is to be used as an estimating tool only.
Use these two tables for roof rafters with a slope greater than 3 in 12.
If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.
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.
Dead load weight of structure and fixed loads 15 lbs ft 2.
Floor joists ceiling joists rafters snow load rafters roof live load deflection limit.
Spacing in 12 16 19 2 24.
Rafter stock size calculator.
1 in 25 4 mm.
The lengths and sizes of joists vary depending on the species and quality of the lumber used.
L 720 l 600 l 480 l 360 l 240 l 180.
To size joists and rafters use the maximum span tables for southern yellow pine.
Rafter and joist span faq.
Click the button to calculate the stock size needed for this job.
Live load 20 lbs ft 2 956 n m 2.
1 psf lb f ft 2 47 88 n m 2.
Input the rafter span on the flat eave overhang and pitch of the roof.
The loads are based on adjusted roof snow loads from the governing building code.
Live load is weight of furniture wind snow and more.
1 ft 0 3048 m.
Area span on the flat.
Use these two tables for roof rafters with a slope of 3 in 12 or less.
2 are indicated below.
Click the button to calculate the stock size needed for this job.
This calculator is to be used as an estimating tool only.
More roof calculators roof truss calculator how to cut rafters.
