Porch Roof Beam Span Chart

Lumber species southern pine douglas fir douglas fir larch hemlock fir spruce pine fir redwood western cedar ponderosa pine red pine.

Porch roof beam span chart.

The smallest beams for patio covers are typically 4 by 6. In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts. Beam span calculator for help simply click on the beside the section you need help with watch this tutorial video. This post may contain affiliate links.

Patio roof maximum beam rafter spans. This means the example porch would need a 6 inch by 8 inch beam. This tells you the size of the beam needed to support the porch s roof. In the example d calculates to 7 75.

If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts. Calculate the initial value for d then round it up to the nearest inch. Window door garage door headers supporting roof loads only. For more information see our disclosures here.

A 4 by 10 can usually span up to 12 feet between posts. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Tables providing size selections for various beam spans and loading combinations for southern pine dimension lumber and southern pine glued laminated timber are available for the following applications.