Standard Wood Roof Truss Sizes

360 mm general truss information.

Standard wood roof truss sizes.

Member size grade tc 1 4 4 7 97 tr26 bc 6 10 72 tr26 bc 10 2 72 tr26 wb 3 8 5. Spans for 2x4 top chord trusses using sheathing other than plywood e g. Standard roof truss general load settings. 600 timber thickness mm.

A truss of this size and larger usually runs a higher figure of around 4 to 4 75 per foot of truss. Essentially a roof truss is a prefabricated frame of supports designed to go on top of a building as it s being built. The steeper the roof the more expensive the trusses get because the longer the boards get and the more roof area increases. 0 524 kn m ceiling dead load.

This truss has a 30 span which is only 4 more than 26 but look how much more webbing there is. Easily attached to the rest of the building s frame they circumvent the complicated expensive nature of from scratch roof framing and can be purchased in a wide variety of designs made from either lumber commonly used for homes or metal primarily used for commercial. Spaced sheathing or 1x boards may be reduced slightly. Standard framing details for use in preliminary design.

Common or standard trusses are symmetrical and have standard four inch heels. Included are a series of representative roof truss span tables that will give you an idea of the truss spans available for a particular load condition load duration lumber type and truss configuration. Trusses must be designed for any special loading such as concentrated loads from hanging partitions or air conditioning units and snow loads caused by driftingnearparapetorslide offfromhigherroofs. The standard roof truss spacing is 2.

The important point to keep in mind when you use your truss calculator is that every truss calculation is completely unique and is based on the size of your roof and its specific dimensions. The truss is a framework consisting of rafters posts and struts which supports your roof. This is the distance between trusses. The webbing is necessary for the strength of the truss and it is needed in a truss this size.

You can use sbca s span charts to roughly determine truss sizes available. Girder trusses are designed to carry additional loads other than standard roof loads. A truss with the same pitch and heel on both sides and a peak at the center is called a common truss. 35 timber size information.