Flat Roof Rafter Span

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.

Flat roof rafter span.

They are nailed securely to exterior wall plates and to each other. Input the rafter span on the flat eave overhang and pitch of the roof. 1 in 25 4 mm. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.

Most roof framing is 24 on center and you can still build sheds up to 14 with 2 4 rafters at 24 on center. 1 ft 0 3048 m. The size of rafters for a flat roof depends on the horizontal span of the building the type and grade of timber used and the load on the roof. The tables below give maximum spans for rafters and beams.

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. 2 4 rafters can span up to 7. Spacing your 2 4 shed rafters at 24 on center limits the width of your roof.

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. Wood beam calculator american wood council website rafter and joist span faq. 2 are indicated below. Click the button to calculate the stock size needed for this job.

1 psf lb f ft 2 47 88 n m 2. Span calculator for wood joists and rafters also available for the android os. Use these two tables for roof rafters with a slope greater than 3 in 12. This is set by the roof use you selected in the previous screen and cannot be modified.

Live load is weight of furniture wind snow and more. Live load overhang kpa. The above spans are based on american softwood lumber standard sizes. The 1 grade.

For light load roofs 24 o c. Rafter span tables use these two tables for roof rafters with a slope of 3 in 12 or less. This calculator is to be used as an estimating tool only. The imposed uniformly distributed live load in the main span.

Input the rafter span on the flat eave overhang and pitch of the roof. Dead load weight of structure and fixed loads 15 lbs ft 2. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. This calculator is to be used as an estimating tool only.

Also available for the android os. The rafters in a flat roof serve as ceiling joists for the space below. For heavy loads 2x4s can span up to 5.