Porch Roof Beam Span Table

The figures are based on quality materials.

Porch roof beam span table.

The total load is 4 000 pounds. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. Fill in the parts of the formula that are already known. 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. The tables below give maximum spans for rafters and beams. For the initial calculation f can be estimated at 1 000. Download a pdf.

F stands for the beam s fiber strength in bending which depends on the species of wood. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Includes size and spacing tables for load bearing and links to related articles. Jan 15 2017 a simple buying guide for beams and rafters that support patio roofs.

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. The smallest beams for patio covers are typically 4 by 6. 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. In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.

In the example the beam spans the 10 foot width of the roof. Tables 7 12. In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts. L stands for the span of the beam in feet.