This demo version is fixed at 1m clear span.
Span flat roof joist wood.
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.
They are ideal for long spans including continuous spans over intermediate supports.
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.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
Dead load weight of structure and fixed loads 15 lbs ft 2.
Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
These span tables apply only to flat roof and roof with a slope of up to 10 degrees.
Span tables for flat roof joists to bs 5268 7 2 imposed loads of 0 75 kn m for maintenance and snow load are applicable where there is no permanent access no fixed ladder or staircase and most areas where the altitude does not exceed 100 metres refer to bs 6399 3.
Span calculator for wood joists and rafters also available for the android os.
1 psf lb f ft 2 47 88 n m 2.
Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.
1 enter joist details 1 1 span and joist spacing.
Also available for the android os.
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.
2 are indicated below.
Common i joist applications i joists are used extensively in residential floor and roof framing.
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.
Live load is weight of furniture wind snow and more.
Flat roof joist calculator.
The full version allows any size.
