Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size.
Flat roof joists span.
The full version allows any size.
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 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.
Live load is weight of furniture wind snow and more.
Span calculator for wood joists and rafters also available for the android os.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
Dead load weight of structure and fixed loads 15 lbs ft 2.
Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.
Trusses with an asterisk that exceed 14 in height may be.
2 are indicated below.
Also available for the android os.
1 ft 0 3048 m.
Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters.
Flat roof joist calculator.
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.
Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12.
To achieve maximum indicated spans trusses may require six or more panels.
This demo version is fixed at 1m clear span.
1 enter joist details 1 1 span and joist spacing.
1 psf lb f ft 2 47 88 n m 2.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
View joist rafter tables.
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.
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.
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.
In these cases 2 inch by 10 inch lumber is often used for ceiling joists although trusses may be more practical.
