You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
Ceiling joist roof span calculator.
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.
For example if building is 24 x 24 and has trusses and the load on the roof will be for 30 lb snow load and a ceiling with no storage will total out like this.
Enter a span for the joist.
Flat roof joists.
Usually 400 450 or.
This is the distance between joist centres.
Flat roof joist calculator.
This demo version is fixed at 1m clear span.
In other words it is either going to be on an outside wall or somewhere on the inside.
The full version allows any size.
1 enter joist details 1 1 span and joist spacing.
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.
Span calculator for wood joists and rafters also available for the android os.
If a room is 10 inside to inside and the joists are cut 10 7 so they will bear fully on both walls then the span will be 10.
This will be slightly less than the length of the board.
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.
The load on an outside wall with clear span trusses is exactly half the load on each wall.
Span calculator for wood joists and rafters also available for the android os.
Joist span tables use these tables to determine lengths sizes and spacing of ceiling joists.
Also available for the android os.