These span tables are the equivalent of other industry standard span tables and are calculated to the same standards.
Flat roof joist span calculator.
To size joists and rafters use the maximum span tables for southern yellow pine.
The full version allows any size.
1 enter joist details 1 1 span and joist spacing.
This is the distance between joist centres.
While every effort has been made to insure the accuracy of the information presented and special effort has been made to assure that the information reflects the state of the art neither the west coast lumber inspection bureau the american wood council nor its members assume any responsibility for any particular design prepared from this online span calculator.
This demo version is fixed at 1m clear span.
The smallest pitch of a roof is 0 5 12.
A completely flat roof is a poor design as water and snow will collect on it eventually leading to your roof collapsing in from the weight of it all.
More roof calculators roof truss calculator how to cut rafters.
Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.
Beams of more than one ply must be fastened together with either nails or bolts.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
This rafter span calculator is species specific for douglas fir hemlock etc.
This span table is to the format and methodology given in bs 5268 7 2.
Also available for the android os.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
These spans were calculated using our flat roof joist calculation engine.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
Click on a span to generate a full calculation you can adjust the exact span.
The truss is a framework consisting of rafters posts and struts which supports your roof.
On longer spans the beam may require much more bearing space as indicated by this table.
Span calculator for wood joists and rafters also available for the android os.
A common choice for flat roofing material is epdm rubber as it is highly durable waterproof and can be made from recycled materials.
Anything 5 and above we always at least double cripple.
According to the 2012 irc codes any beam joist or header shall never have a bearing of less than 1 1 2.
The important point to keep in mind when you use your truss calculator is that every truss calculation is completely unique and is based on the size of your roof and its specific dimensions.
Notches are not to exceed 0 125 of the depth of the joist and are to be located between 0 07 and 0 25 of the span from the support.
