Tables in the span book and the national building code were both generated by the canadian wood council.
Roof beam span tables canada.
For lesser grades spans should be shorter.
The canadian wood council s beam calculator has been developed for the purpose of information only.
For each application a pdf download is available.
Anything 5 and above we always at least double cripple.
The tables below give maximum spans for rafters and beams.
Also see assumptions for table development.
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.
On longer spans the beam may require much more bearing space as indicated by this table.
The span book is a supplement to the wood joist rafter and beam spans found in the national building code of canada.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
Although all possible efforts have been made to ensure that the information from this tool is accurate the cwc cannot guarantee the completeness accuracy or exactness of the information.
The national building code references the span book as follows.
The figures are based on quality materials.
Dimensional lumber deck beam span chart.
Refer to sfpa s publication southern pine headers beams download in publications that includes all size selection and allowable load tables.
According to the 2012 irc codes any beam joist or header shall never have a bearing of less than 1 1 2.
Span calculator for wood joists and rafters also available for the android os.
Also available for the android os.
Keep in mind that these are maximums in other words shortening spans slightly will result in a more solid structure.
Loading conditions are detailed below.
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.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
A double 2x12 beam can span 12 feet.
A 2 2x10 can span 10 feet and so on.
The numbers in gray indicate the distance between the support posts.
