Timber Roof Beam Sizes

Starting from scratch with no previous knowledge of structures required.

Timber roof beam sizes.

This is the distance between joist centres. In the example the beam spans the 10 foot width of the roof. For the initial calculation f can be estimated at 1 000. Click on a span to generate a full calculation you can adjust the exact span.

Roof pitch between 30 and 45 degrees strength class c16 size of purlins in mm maximum clear span 1 5m maximum clear span 1 8m maximum clear span 2 1m maximum clear span 2 4m maximum clear span 2 7m. 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. The total load is 4 000 pounds. Beam sizes and properties beam size bxd nominal section area 10 mm 35x70 2 45 35x90 3 15 35x120 4 2 35x140 4 9 35x190 6 65 45x90 4 05 45x140 6 3.

L stands for the span of the beam in feet. Tiled roof with ceiling 75 timber floor with floor boards 40 tiled or heavy floors 95 live loads kg m kg m floor domestic 200. Staggered pattern with at least a 3 x 120 nail. Here s how to calculate the size of a timber beam you need to span a given distance.

Fill in the parts of the formula that are already known. The 2012 irc code calls for a minimum of a 32 o c. This span table is to the format and methodology given in bs 5268 7 2. Rafter to ridge beam connection framing roof ceiling construction structural ridge beam absolute deflection in a ridge beam structural ridge beam tricks of the trade.

A 8x12 beam will net an overall 7 x 11. Find the column for your dead load and spacing and the row for your timber size to find the permissible clear span in metres. Usually 400 450 or 600mm but any value can be used up to 610mm max 1 2 timber strength class and joist size automatically calculate sizes suitable for supporting the loads below. For simple construction such as domestic construction this can be determined from span table supplements in as1684 2 and as1684 3.

Stress grades and timber sizes combine to determine the spanning ability of load carrying members. These spans were calculated using our flat roof joist calculation. Ridge beam statics in timber framing log construction. F stands for the beam s fiber strength in bending which depends on the species of wood.

Versa lam lvl size chart laminated beam span tables charts. Our heavy timber beams are cut to standard dimensions. We have learned from our experience to use at least a 3 1 4 x 131 groove shank nail in a column of four every foot apart down the laminate.