Roof Joist Member Thickness

Here we have a wood framed gable roof.

Roof joist member thickness.

9 16 tji joists design properties 6 floor span and load tables 7 8 tips for preventing floor noise 8 allowable holes 9 cantilevers 10 11 roof span and load tables 12 13 framing. For instance if your roof has a steep pitch you may be able to use 2 inch by 4 inch rafters but if your roof has a low pitch building code may require that you used 2 inch by 6 inch or 2 inch by 8 inch rafters. 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. Span calculator for wood joists and rafters also available for the android os.

This is the distance between joist centres. The lengths and sizes of joists vary depending on the species and quality of the lumber used. Wood beam calculator american wood council website rafter and joist span faq. Fire safe construction 3 floor performance and tj pro rating 4 5 section 1.

Floor beam span tables of residential structural design we will now look at roof rafter and beam design. Trus joist tji joist specifier s guide tj 4000 july 2019. The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial. For low pitch roofs building codes may require larger dimension rafters.

Let s consider a basic gable wood roof framing design.