Porch Roof Beam Span Chart

You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.

Porch roof beam span chart.

A 4 by 10 can usually span up to 12 feet between posts. This means the example porch would need a 6 inch by 8 inch beam. Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads. Window door garage door headers supporting roof loads only.

This post may contain affiliate links. For more information see our disclosures here. Beam span calculator for help simply click on the beside the section you need help with watch this tutorial video. In the example d calculates to 7 75.

Calculate the initial value for d then round it up to the nearest inch. Patio roof maximum beam rafter spans. Window door garage door headers supporting roof wall floor loads. In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts.

This tells you the size of the beam needed to support the porch s roof. The smallest beams for patio covers are typically 4 by 6. If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts.