Roof rafter span use this table to determine the maximum lengths of roof rafters based on species and grade of lumber spacing dimensions load and slope.
Flat roof joists span.
Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size.
The full version allows any size.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
View joist rafter tables.
Trusses with an asterisk that exceed 14 in height may be.
1 psf lb f ft 2 47 88 n m 2.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
This demo version is fixed at 1m clear span.
Live load is weight of furniture wind snow and more.
Flat roof joist calculator.
Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters.
2 are indicated below.
1 enter joist details 1 1 span and joist spacing.
Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12.
1 ft 0 3048 m.
Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.
Span ft 1 5 2 0 2 5 3 0 3 5 2 30 22 18 15 13 4 59 44 36 30 25 6 89 67 53 44 38 8 119 89 71 59 51 10 148 111.
To achieve maximum indicated spans trusses may require six or more panels.
Also available for the android os.
In these cases 2 inch by 10 inch lumber is often used for ceiling joists although trusses may be more practical.
Span tables for joists and rafters 3 american wood council table 9 1 required compression perpendicular to grain design values f c in pounds per square inch for simple span joists and rafters with uniform load.
Flat the most economical flat truss for a roof is provided when the depth of the truss in inches is approximately equal to 7 of the span in inches.
While every effort has been made to insure the accuracy of the information presented and special effort has been made to assure that the information reflects the state of the art neither the west coast lumber inspection bureau the american wood council nor its members assume any responsibility for any particular design prepared from this online span calculator.
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.
Span calculator for wood joists and rafters also available for the android os.
Spans for joists greater than 20 feet that are parallel to the rafters require a 12 inch joist spacing when using 2 inch by 10 inch 2 douglas and hemlock fir or southern pine or 16 inch spacing when using 2 inch by 10 inch 2.
