Safe Spans For No 1 Roof Rafters

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.

Safe spans for no 1 roof rafters.

View joist rafter tables. 1 psf lb f ft 2 47 88 n m 2. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. An essential part of planning a patio roof or gazebo project is determining the number size and spacing of rafters beams and posts according to the loads they will carry.

Dead load weight of structure and fixed loads 15 lbs ft 2. 2 are indicated below. Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12. 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.

This table is simply a sample and may not be valid for your region. 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. 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.

Sample maximum spans feet inches douglas fir or larch no 1 or no 2 with 31 3 psf of snow loading. 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. 1 ft 0 3048 m. 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.

This post may contain affiliate links. Span calculator for wood joists and rafters also available for the android os. Live load is weight of furniture wind snow and more. Patio roof maximum beam rafter spans.

Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. Span calculator for wood joists and rafters available for the iphone. For more information see our disclosures here.