Porch Roof Beam Span Chart

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.

Porch roof beam span chart.

This post may contain affiliate links. A 4 by 10 can usually span up to 12 feet between posts. This tells you the size of the beam needed to support the porch s roof. This means the example porch would need a 6 inch by 8 inch beam.

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. In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts. The smallest beams for patio covers are typically 4 by 6.

Calculate the initial value for d then round it up to the nearest inch. Patio roof maximum beam rafter spans. Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads. For more information see our disclosures here.

Lumber species southern pine douglas fir douglas fir larch hemlock fir spruce pine fir redwood western cedar ponderosa pine red pine. 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. In the example d calculates to 7 75.