What roof truss means
A roof truss is a factory built triangle of lumber joined with metal plates. Trusses replace rafters and ceiling joists on most new houses.
Where it matters on a roofing job
You cannot cut, notch or drill a truss without the maker's or an engineer's sign off, which matters when a customer wants an attic fan or a skylight between them. Write that limit into the scope so nobody improvises on site.
What the model code says
- Cutting, notching or drilling trusses is prohibited unless the manufacturer or a design professional allows it. (IRC 2021, Chapter 5)
Check which code edition your building department enforces for roof truss before you quote.
Work it out
- Free calculator: Framing calculator
- Licensing: Roofing license rules by state
- Tools, templates and guides: Free roofing resources
Sources: 2021 International Residential Code, Chapter 5, Floors (ICC). Checked October 9, 2026.