Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings.
Wood beam span table uk.
It is assumed that for built in joists that the masonry is 100mm wide and for joists on hangers the hanger has a 75mm bottom plate.
For pitched roofs flat roofs and ceiling joists.
The numbers in gray indicate the distance between the support posts.
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.
Allowable load tables tables providing size selections for various beam spans and loading combinations for southern pine dimension lumber and southern pine glued laminated timber are available for the following applications.
Size selection tables headers beams.
A 2 2x10 can span 10 feet and so on.
Centres is the maximum centres that this joist can be used for in this application.
This should be compared to the table.
0 003 x engineering span or 12mm whichever is lesser.
This table is for a dead load of more than 0 25 but not more than 0 50 and allows for an imposed loading of no more than 1 5 kn sq m.
Other span tables are based on the guidance given in bs 5268 7 1 which is a uniformly distributed load of 1 5kn m for spans greater than 2400 mm and 3 6 kn load per metre width of floor for spans less than 2400 mm to ensure that very small joist sizes do not result from the calculations for smaller spans.
You need to measure the complete span of your floor joists together with the distance between them the centres and the size of the timbers.
When supporting joists that span 12 feet with no overhang beyond the beam a double ply beam can span in feet a value equal to its depth in inches.
Our floor joist span tables are based on loadings given in the newer amended version of bs 6399 1.
Span calculator for wood joists and rafters also available for the android os.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
Dimensional lumber deck beam span chart.
A double 2x12 beam can span 12 feet.
This means that some values are slightly more conservative than span tables from other sources if those do not include the amended guidance.
They refer to a dead load of not more than 0 5kn m 2 excluding the weight of the joist and an imposed load not exceeding 1 5 kn m 2.
Headers beams.
Span tables for domestic floor joists to bs 5268 7 1 note.