DIY Roof Truss Plans
A DIY truss "plan" starts with the same numbers a professional plan uses — span, pitch, spacing, and load. This calculator generates those core dimensions for your project; for anything requiring a building permit, pair it with an engineered, stamped plan from a truss manufacturer.
Generate Your Truss Dimensions
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.
DIY Plans vs. Engineered Truss Plans
A DIY truss plan sketched from this calculator's span, pitch, and dimension outputs is useful for small, unpermitted structures (a garden shed, a lean-to) where the load and span are modest and the consequences of an oversized safety margin are low.
An engineered truss plan goes further: it specifies exact lumber grade, connector plate size and placement at every joint, web member layout, and a stamped calculation showing the design meets your local building code's load requirements. Most residential and commercial permits require this level of documentation, not a DIY sketch.
For a house, garage, or any permitted structure, take this calculator's span and load numbers to a local truss manufacturer or structural engineer — they will produce the stamped plan required for permit approval, typically at low or no cost when you purchase the trusses through them.
Frequently Asked Questions
Can I use a DIY truss plan for a permitted building?
Generally no — most building departments require a stamped, engineered truss design for permitted structures like houses and garages. DIY plans are typically only appropriate for small, unpermitted structures like garden sheds.
Where can I get free engineered truss plans?
Truss manufacturers typically include engineering and a stamped plan as part of a truss purchase at little or no extra cost — it is usually more cost-effective to buy engineered trusses than to commission stand-alone plans.