Keep in mind that these are maximums in other words shortening spans slightly will result in a more solid structure.
Post and beam roof span tables.
Here we have a wood framed gable roof.
A double 2x12 beam can span 12 feet.
On longer spans the beam may require much more bearing space as indicated by this table.
View joist rafter tables.
The determining factor of post spacing is the allowable span of your beams.
The numbers in gray indicate the distance between the support posts.
The tables below give maximum spans for rafters and beams.
The full table shows more lumber sizes.
Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters.
The figures are based on quality materials.
Allowable spans vary according to wood species and the loads that the beam will bear such as snow loads or the dead loads of construction materials.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
Numbers in blue are joist spans beam to beam or house to beam.
There are several beam span tables for all 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.
A 2 2x10 can span 10 feet and so on.
According to the 2012 irc codes any beam joist or header shall never have a bearing of less than 1 1 2.
Dimensional lumber deck beam span chart.
Anything 5 and above we always at least double cripple.
Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12.
It also shows the maximum that the beam can span.
Sample floor beam span table.
Beams of more than one ply must be fastened together with either nails or bolts.
Continuing on from part 3.
Let s consider a basic gable wood roof framing design.
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.
This span table excerpt shows two possible sizes of built up floor beams 2 x 10 and 2 x 12.
In other words the maximum distance it can cover without support from posts.
This table is simply a sample and may not be valid for your region.
Patio roof maximum beam rafter spans.
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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.
