Span A Slope Roof With Lumber

The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.

Span a slope roof with lumber.

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. 1 ft 0 3048 m. Dead load weight of structure and fixed loads 15 lbs ft 2. Consult local building codes for snow load capacity and reference the span tables for joists and rafters published by the american wood council awc as a general rule roofs that have a high human occupancy rate should be framed with rafters every 16.

Floor beam span tables of residential structural design we will now look at roof rafter and beam design. 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. 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. Let s consider a basic gable wood roof framing design.

These numbers are for roofs supporting light loads of 20 pounds for square foot. 1 psf lb f ft 2 47 88 n m 2. 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. An spf roof at the same spacing and lumber size will span 11.

Can span up to 13 4. Live load is weight of furniture wind snow and more. Also available for the android os. The thickness of plywood used for roof decking depends on the roof slope the spacing of rafters and the weight of other material to be put over the decking as well as the design load the.

2 are indicated below. That means it can span a total length of over 26 for a gable roof. Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. Continuing on from part 3.

An syp 2 6 rafter at 24 o c. There are also factors such as deflection elasticity and wood species that come in to play. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. Here we have a wood framed gable roof.

Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. The tables below give maximum spans for rafters and beams. In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.