Safe Spans For No 1 Roof Rafters

The tables permit a bearing length of up to 3 5 inches but since 1 5 is probably the worst case that you ll encounter for joist or rafter bearing it s a safe value.

Safe spans for no 1 roof rafters.

Live load is weight of furniture wind snow and more. Calculations determine the maximum spacing based on the material used rafter size and load the roof needs to hold so that the roof is safe and meets all building codes. Sample maximum spans feet inches douglas fir or larch no 1 or no 2 with 31 3 psf of snow loading. 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.

Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters. 1 ft 0 3048 m. This table is simply a sample and may not be valid for your region. This post may contain affiliate links.

Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. Table 9 1 in span tables for joists and rafters figure 5 gives a required compression value of 237 psi for a span of 16 feet and bearing length of 1 5 inches. For more information see our disclosures here. The maximum spans in the table above are for the horizontal distance the rafter can span not the diagonal distance or actual length of the rafter.

Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. The 1 grade material is more expensive than the 2 grade but if you can use fewer or smaller 1 grade joists or rafters in your design you may actually save money. Although there is not one standard rafter spacing measurement many builders follow standard increments for simplicity. Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12.

Span calculator for wood joists and rafters available for the iphone. 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. Patio roof maximum beam rafter spans. 2 are indicated below.

View joist rafter tables. Dead load weight of structure and fixed loads 15 lbs ft 2. Span calculator for wood joists and rafters also available for the android os.