How to Build a Roof Truss
Building a roof truss follows five stages: size the truss with span and pitch, lay out the pattern on a flat surface, cut each member, assemble and plate the joints, then brace and lift it into place. Use the calculator below to get your exact dimensions before cutting any lumber.
Step 1: Size Your Truss
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Live Roof Diagram
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The Five Stages of Building a Truss
1. Size it. Use your span, pitch, and overhang to calculate top chord length, bottom chord length, and overall height — the calculator above gives every dimension at once. 2. Lay it out. Snap chalk lines on a flat surface (a truss table or a clean slab) at the exact chord lengths and angle, then use the layout as a template for every truss in the run so they are all identical.
3. Cut the members. Cut top chords, bottom chord, and web members to length and angle, following your layout exactly — even small angle errors compound across a truss and cause a poor fit at the ridge or supports. 4. Assemble and plate. Position every member on the layout, then fasten joints with construction adhesive and nail plates, or press punched metal connector plates into both faces of each joint with a hydraulic press for factory-grade trusses.
5. Brace and install. Temporary bracing keeps trusses plumb and straight until permanent bracing and sheathing are installed; trusses are lifted into place at the calculated spacing and fastened to the wall top plate with hurricane ties or approved connectors per your local code. For anything beyond a small shed span, have the truss design reviewed by an engineer before building — see our engineering disclaimer.
Frequently Asked Questions
Can I build my own roof trusses?
For small structures like sheds (typically under 12-16 ft span), many builders successfully build simple trusses on site. For house-scale spans and anything requiring a building permit, use factory-engineered trusses or have a DIY design reviewed and stamped by a structural engineer first.
What tools do you need to build a truss?
At minimum: a circular saw for cutting chords and webs to angle, a speed square for marking angles, a tape measure, construction adhesive, and either nail plates or punched connector plates (a hydraulic press is used for factory-grade plates but is not required for small DIY builds using nail plates).
How long does it take to build a truss?
Once a layout template is set up, an experienced framer can cut and assemble a simple truss in under an hour; the layout and first prototype truss typically take longest since every subsequent truss in the run copies that template exactly.