More roof calculators roof truss calculator how to cut rafters.
Flat roof joist span calculator.
The truss is a framework consisting of rafters posts and struts which supports your roof.
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.
The smallest pitch of a roof is 0 5 12.
On longer spans the beam may require much more bearing space as indicated by this table.
These span tables are the equivalent of other industry standard span tables and are calculated to the same standards.
A common choice for flat roofing material is epdm rubber as it is highly durable waterproof and can be made from recycled materials.
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.
This demo version is fixed at 1m clear span.
Click on a span to generate a full calculation you can adjust the exact span.
According to the 2012 irc codes any beam joist or header shall never have a bearing of less than 1 1 2.
To size joists and rafters use the maximum span tables for southern yellow pine.
Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.
Anything 5 and above we always at least double cripple.
This span table is to the format and methodology given in bs 5268 7 2.
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.
This rafter span calculator is species specific for douglas fir hemlock etc.
The full version allows any size.
This is based upon the span of the rafter horizontal span not total rafter length live and dead loads.
Beams of more than one ply must be fastened together with either nails or bolts.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
These span tables apply only to flat roof and roof with a slope of up to 10 degrees.
Span calculator for wood joists and rafters also available for the android os.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
These spans were calculated using our flat roof joist calculation engine.
This is the distance between joist centres.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
Flat roof joist calculator.
