Floor beam span tables of residential structural design we will now look at roof rafter and beam design.
Lumber spans for roofs.
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.
Let s consider a basic gable wood roof framing design.
Span calculator for wood joists and rafters also available for the android os.
Live load is weight of furniture wind snow and more.
Continuing on from part 3.
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.
Dead load weight of structure and fixed loads 15 lbs ft 2.
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.
1 ft 0 3048 m.
The tables below give maximum spans for rafters and beams.
Wood beam calculator american wood council website rafter and joist span faq.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.
Also available for the android os.
The lengths and sizes of joists vary depending on the species and quality of the lumber used.
The figures are based on quality materials.
In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.