Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12.
Lumber span tables 2x4 flat roof rafters.
Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.
Spacing your 2 4 shed rafters at 24 on center limits the width of your roof.
For light load roofs 24 o c.
2 are indicated below.
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.
Permitted for intermediate spans and design values.
Tables w 1 and w 2 of design values for joists and rafters a supplement to these span tables provide such values for the most commonly used.
View joist rafter tables.
Also available for the android os.
Span calculator for wood joists and rafters also available for the android os.
Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters.
1 psf lb f ft 2 47 88 n m 2.
Strength live load of 30 psf plus dead load of 10 psf determines the required bending design value.
Deflection for 30 psf live load.
2 4 rafters can span up to 7.
Limited to span in inches divided by 360.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
Ceiling joist span use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size.
Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch.
Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall.
Live load is weight of furniture wind snow and more.
Dead load weight of structure and fixed loads 15 lbs ft 2.
Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.
Span tables for jois ts and rafters american wood council 4 span tables for joists and rafters american wood council design criteria.
Lumber design values use of these span tables requires reference to the applicable design values for the various species and grades of lumber.
1 ft 0 3048 m.
