Span A Slope Roof With Lumber

An spf roof at the same spacing and lumber size will span 11.

Span a slope roof with lumber.

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. The figures are based on quality materials. 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. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.

Floor beam span tables of residential structural design we will now look at roof rafter and beam design. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. 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. The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.

Continuing on from part 3. 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. Difference in slope between the top and bottom chords is at least 3 12 or the bottom chord pitch is no more than half the top chord pitch. In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.

Live load is weight of furniture wind snow and more. 2 are indicated below. Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. 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.

These numbers are for roofs supporting light loads of 20 pounds for square foot. There are also factors such as deflection elasticity and wood species that come in to play. 1 psf lb f ft 2 47 88 n m 2. The tables below give maximum spans for rafters and beams.

Also available for the android os. Let s consider a basic gable wood roof framing design. Can span up to 13 4. An syp 2 6 rafter at 24 o c.

Here we have a wood framed gable roof. Span calculator for wood joists and rafters also available for the android os. That means it can span a total length of over 26 for a gable roof.