Continuing on from part 3.
Lumber spans for roofs.
Also available for the android os.
Wood beam calculator american wood council website rafter and joist span faq.
The tables below give maximum spans for rafters and beams.
Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.
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.
Live load is weight of furniture wind snow and more.
2 are indicated below.
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.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
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.
The figures are based on quality materials.
The lengths and sizes of joists vary depending on the species and quality of the lumber used.
In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
Dead load weight of structure and fixed loads 15 lbs ft 2.
Floor beam span tables of residential structural design we will now look at roof rafter and beam design.
Let s consider a basic gable wood roof framing design.
The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.
1 psf lb f ft 2 47 88 n m 2.