Roof Rafter Size Span

Live load 20 lbs ft 2 956 n m 2.

Roof rafter size span.

For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2. Rafter and joist span faq the lengths and sizes of joists vary depending on the species and quality of the lumber used. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. Spacing in 12 16 19 2 24.

This calculator is to be used as an estimating tool only. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. 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.

Rafter stock size calculator. 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. Our roof rafter calculator tools are handy for calculating the number of rafters needed rafter length calculator lineal feet of rafter board feed in ridge and sub facia and the total board feet in the roof.

Rafter stock size calculator. Floor joists ceiling joists rafters snow load rafters roof live load deflection limit. Click the button to calculate the stock size needed for this job. Click the button to calculate the stock size needed for this job.

2 are indicated below. Area span on the flat. 1 in 25 4 mm. 3 stud construction standard utility.

Live load is weight of furniture wind snow and more. It is always better to have a large rafter rather than be concerned with a sagging roof. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. Input the rafter span on the flat eave overhang and pitch of the roof.

Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. This calculator is to be used as an estimating tool only. Includes result for hip valley factor slope factor and the roof slope in degrees. 2x4 2x6 2x8 2x10 2x12.

Rafter length using angle v r 2cos a rafter length using pitch v r 2 sqrt 1 p 2 where v overhang r roof span p pitch. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.