APB » Roof Trusses

Roof Trusses

A truss is a triangular shaped structure made of dimensional lumber designed to withstand anticipated loads at your building site.

Loading, like snow load, wind, loft, ceiling, or attic loads are all considerations when a truss is designed. The top cord is sized taking snow load into consideration. The bottom cord is where loft, ceiling, and attic loads are factored in.

Large loads on either cord (top or bottom) can impact the size of the dimensioned lumber used, not only on the large load side, but on the other side as well.

Truss Terminology      Snow Load      Roof Material Weights

Truss Erection & Handling

The larger the truss the more difficult it is to handle effectively. Roof trusses are engineered to be strong in plane with the roofing on the top chord. They are easily damaged when laying on their side.

Large span trusses require multiple pickup points using a spreader bar on the crane. For example you might use a 35' spreader bar on a 70' span truss.

Truss Bracing

temporary truss bracing Temporary truss bracing is critical to ensure safety and to protect the integrity of the truss structure until permanent bracing is in place.

For detailed information see our page on permanent roof truss bracing.



Truss Connection Details

Connecting the truss to your building is critical to long term strength, durability, and safety.

Post frame buildings have some advantages that are important to consider in your construction methods.

Full height gable posts, Simpson H2.5a rafter ties, 1/2" carriage bolts on 2 2x12 truss carriers will do the job using proper techniques and equipment. For detailed drawings visit our truss connection details page.

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