Roof Truss Load Calculator
Every roof truss must be sized for the loads it will actually carry — its own weight, occupants and maintenance workers, snow, and wind. This roof truss load calculator combines dead load, live load, snow load, and wind load into a total roof weight estimate.
Calculate Your Roof Truss Loads
Enter your building specifications below. Results and the roof diagram update live as you type.
Live Roof Diagram
Results
Estimate Your Project Budget
Automatically calculated from your inputs above in the calculator.
Estimates only. Actual costs vary by region, supplier, and site conditions.
Load Calculation of Roof Trusses
Dead load is the permanent weight of the roofing material, decking, insulation, and the truss members themselves — it varies mainly by your material choice (SPF, Douglas Fir, engineered wood, or steel).
Live load covers temporary weight such as maintenance workers and equipment on the roof, and is set by a standard code minimum (commonly 20 psf for residential sloped roofs) rather than by user input.
Snow load and wind load are climate- and code-dependent, so enter your local values from your building department's snow and wind maps — the calculator adds these to dead and live load to give a combined total design load and estimated roof weight.
Frequently Asked Questions
Load calculation of roof truss
Total design load combines dead load (permanent material weight), live load (maintenance/occupancy, typically 20 psf), snow load, and wind load. Enter your local snow and wind values above to see the combined total.
What is wind load and why does it matter?
Wind load is the pressure exerted on a roof by wind. It matters because excessive uplift can cause structural failure in high-wind regions — always use your local code's wind load value, not a guess.