Porch Roof Beam Span Table

Jan 15 2017 a simple buying guide for beams and rafters that support patio roofs.

Porch roof beam span table.

The smallest beams for patio covers are typically 4 by 6. Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. The total load is 4 000 pounds.

Download a pdf. In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts. The tables below give maximum spans for rafters and beams. For the initial calculation f can be estimated at 1 000.

A 4 by 10 can usually span up to 12 feet between posts. F stands for the beam s fiber strength in bending which depends on the species of wood. If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts. Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.

Includes size and spacing tables for load bearing and links to related articles. In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. Tables 7 12. Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.

L stands for the span of the beam in feet. The figures are based on quality materials. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Fill in the parts of the formula that are already known.