Lumber Spans For Roofs

Let s consider a basic gable wood roof framing design.

Lumber spans for roofs.

Span calculator for wood joists and rafters also available for the android os. Continuing on from part 3. Dead load weight of structure and fixed loads 15 lbs ft 2. The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.

For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. For example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine. The lengths and sizes of joists vary depending on the species and quality of the lumber used. The tables below give maximum spans for rafters and beams.

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. 2 are indicated below. Here we have a wood framed gable roof.

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. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. Wood beam calculator american wood council website rafter and joist span faq. Floor beam span tables of residential structural design we will now look at roof rafter and beam design.

1 ft 0 3048 m. Also available for the android os.