Porch Roof Beam Span Chart

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Porch roof beam span chart.

Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads. F stands for the beam s fiber strength in bending which depends on the species of wood. 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. The smallest beams for patio covers are typically 4 by 6.

L stands for the span of the beam in feet. This post may contain affiliate links. In the example the beam spans the 10 foot width of the roof. Patio roof maximum beam rafter spans.

For the initial calculation f can be estimated at 1 000. The total load is 4 000 pounds. If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts. 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. 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. Window door garage door headers supporting roof wall floor loads.