Standard Roof Truss Timber Sizes

The structure is similar to a conventional scotch valley without the lay boards.

Standard roof truss timber sizes.

The shapes and spans shown here represent only a fraction of the millions of designs produced by alpine engineers. 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. Alpine truss designs are engineered to meet specific span configuration and load conditions. Member size grade tc 1 4 4 7 97 tr26 bc 6 10 72 tr26 bc 10 2 72 tr26 wb 3 8 5 9 72 tr26 wb 4 8 4 9 72 tr26.

A standard overhang is 16 24 inches but the overhang can be any length you wish. The institute for timber construction south africa itc sa south africa s saqa accredited professional body safeguarding the local timber industry for over 45 years shares industry insight on structural timber as a material standard available dimensions as well as standard truss types and profiles. Roof pitch between 15 and 22 5 degrees with rafter spacing strength. Roof pitch between 15 and 22 5 degrees with rafter spacing strength class c16.

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. A truss with the same pitch and heel on both sides and a peak at the center is called a common truss. Usually 400 450 or 600mm but any value can be used up to 610mm max. Girder trusses are designed to carry additional loads other than standard roof loads.

If the overhang exceeds 2 5 feet we will need to use a larger top chord for the overhang typically a 2 6 top chord for the truss. Common or standard trusses are symmetrical and have standard four inch heels. We can also build a cantilever for the overhang which is where the bottom chord of the truss continues beyond the wall. Roof pitch between 15 and 22 5 degrees with rafter spacing.

The truss is a framework consisting of rafters posts and struts which supports your roof. Maximum clear span of rafters in metres for roof pitches of between 15 and 45 degrees. This is the distance between rafter centres. 600 timber thickness mm.

All truss images are for visual aid only and may not truly represent the roof truss supplied or designed by your chosen supplier.