Porch Roof Beam Span Chart

Window door garage door headers supporting roof wall floor loads.

Porch roof beam span chart.

A 4 by 10 can usually span up to 12 feet between posts. Window door garage door headers supporting roof loads only. Calculate the initial value for d then round it up to the nearest inch. This post may contain affiliate links.

An essential part of planning a patio roof or gazebo project is determining the number size and spacing of rafters beams and posts according to the loads they will carry. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Beam span calculator for help simply click on the beside the section you need help with watch this tutorial video. If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts.

For more information see our disclosures here. In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts. 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. Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.

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