Timber Roof Beam Sizes

All the figures are based on roofing tiles or slates laid on timber laths over sarking felt.

Timber roof beam sizes.

Our heavy timber beams are cut to standard dimensions. Find the column for your dead load and spacing and the row for your timber size to find the permissible clear span in metres. The following tables give details of the allowable spans and spacing for some of the more common timber sizes used in traditional roofing construction. Starting from scratch with no previous knowledge of structures required.

Aitc beam capacity tables. If there is are any questions about anything else then you should contact your supplier or an engineer. Pitched roof timber sizes. 1 2 timber strength class and joist size automatically calculate sizes suitable for supporting the loads below c16 cost effective for most applications c24 stronger more demanding c14 c18 c22 c27 c30 c35 c40.

Click on a span to generate a full calculation you can adjust the exact span. Per wwpa guidelines for standard dimension timbers a nominal 4 x6 timber nets to 3 x5 actual dimensions after it has been sawn all beams larger than 8 inch will mill to the inch. Stress grades and timber sizes combine to determine the spanning ability of load carrying members. It has been my experience to never use a beam smaller than a two ply 2 x 8.

A 8x12 beam will net an overall 7 x 11. Aitc capacity tables provide the uniformly distributed load that a glued laminated timber beam can support based on beam size span and material properties. In the example d calculates to 7 75. Calculate the initial value for d then round it up to the nearest inch.

Designing with roof rafter span tables lvl 2 0e 2900fb power beam anthony forest s co raising ceiling joists jlc roofdek manual structural roof decking and trays. This means the example porch would need a 6 inch by 8 inch beam. Most interior beams need to include the roof load. Here s how to calculate the size of a timber beam you need to span a given distance.

Table specifications are provided with each table indicating conditions and assumptions used to calculate the loads. Span tables allow users to choose an appropriate size and stress grade to achieve spanning needs. These tables are provided as a guideline. This calculator matches up with 90 of the applications in the 2012 international residential code book.

For simple construction such as domestic construction this can be determined from span table supplements in as1684 2 and as1684 3.