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.

Roof rafter size span.

Rafter and joist span faq the lengths and sizes of joists vary depending on the species and quality of the lumber used. Click the button to calculate the stock size needed for this job. 1 ft 0 3048 m. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.

Floor joists ceiling joists rafters snow load rafters roof live load deflection limit. This calculator is to be used as an estimating tool only. It is always better to have a large rafter rather than be concerned with a sagging roof. Rafter stock size calculator.

3 stud construction standard utility. 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. This calculator is to be used as an estimating tool only. Use our online rafter length calculator to quickly compute the length of the shed roof rafter by entering the measurements of overhead length of roof span pitch or angle.

If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. Live load 20 lbs ft 2 956 n m 2. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. Click the button to calculate the stock size needed for this job.

1 in 25 4 mm. Dead load weight of structure and fixed loads 15 lbs ft 2. 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. Area span on the flat.

Input the rafter span on the flat eave overhang and pitch of the roof. Live load is weight of furniture wind snow and more. 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. 1 psf lb f ft 2 47 88 n m 2.

2x4 2x6 2x8 2x10 2x12. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. 2 are indicated below. Spacing in 12 16 19 2 24.

If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Input the rafter span on the flat eave overhang and pitch of the roof.