Fill in the parts of the formula that are already known.
Patio roof beam span table.
The smallest beams for patio covers are typically 4 by 6.
In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts.
F stands for the beam s fiber strength in bending which depends on the species of wood.
The tables permit a bearing length of up to 3 5 inches but since 1 5 is probably the worst case that you ll encounter for joist or rafter bearing it s a safe value.
Download a pdf.
The tables below give maximum spans for rafters and beams.
Includes size and spacing tables for load bearing and links to related articles.
Flat roof span tables allow for a maximum roof pitch of 5º.
Use recommended minimum roof pitches as specified by roof sheet supplier.
L stands for the span of the beam in feet.
For the initial calculation f can be estimated at 1 000.
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.
The total load is 4 000 pounds.
Table 9 1 in span tables for joists and rafters figure 5 gives a required compression value of 237 psi for a span of 16 feet and bearing length of 1 5 inches.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
Tables 7 12.
Posts these span tables are designed for a minimum post size of 50 x 50 x 2 5mm up to a maximum height of 3 0m.
Jan 15 2017 a simple buying guide for beams and rafters that support patio roofs.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
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.
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.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts.
A 4 by 10 can usually span up to 12 feet between posts.
