Span A Slope Roof With Lumber

The tables below give maximum spans for rafters and beams.

Span a slope roof with lumber. An spf roof at the same spacing and lumber size will span 11. Also available for the android os. Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. These numbers are for roofs supporting light loads of 20 pounds for square foot.

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

Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. Let s consider a basic gable wood roof framing design. Floor beam span tables of residential structural design we will now look at roof rafter and beam design. That means it can span a total length of over 26 for a gable roof.

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. 1 ft 0 3048 m. 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. An syp 2 6 rafter at 24 o c. Can span up to 13 4. 2 are indicated below.

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. 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. Span calculator for wood joists and rafters also available for the android os. Live load is weight of furniture wind snow and more.

In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. The figures are based on quality materials. 1 psf lb f ft 2 47 88 n m 2.