Roof Load Beam Span

The theoretical size of a load bearing beam required to support a particular weight is easy to calculate but the choice of the actual beam depends on taking into account the factors of the particular situation.

Roof load beam span.

For the initial calculation f can be estimated at 1 000. It is important to list live load dead load and total load separately because live load is used to compute stiffness and total load is used to calculate strength. Window door garage door headers supporting roof loads only. Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.

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. 15 psf x 14ft 210 pounds per lineal foot. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.

In the example the beam spans the 10 foot width of the roof. Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. 910 pounds per lineal foot. L stands for the span of the beam in feet.

Window door garage door headers supporting roof wall floor 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.