Roof Joist Member Thickness

The lengths and sizes of joists vary depending on the species and quality of the lumber used.

Roof joist member thickness.

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. Fire safe construction 3 floor performance and tj pro rating 4 5 section 1. For low pitch roofs building codes may require larger dimension rafters.

Let s consider a basic gable wood roof framing design. Continuing on from part 3. Trus joist tji joist specifier s guide tj 4000 july 2019. Usually 400 450 or 600mm but any value can be used up to 610mm max usually 400 450 or 600mm but any value can be used up to 610mm max 1 2 timber strength class and joist size.

Here we have a wood framed gable roof. Wood beam calculator american wood council website rafter and joist span faq. Also available for the android os. Floor beam span tables of residential structural design we will now look at roof rafter and beam design.

Span calculator for wood joists and rafters also available for the android os.