What ridge board means
A ridge board is the horizontal board at the peak that the tops of the rafters frame against. It lines the rafters up but does not carry them on its own.
Where it matters on a roofing job
A ridge board is different from a structural ridge beam, which holds the rafters up and sits on posts. On a vaulted ceiling remodel, the difference decides whether ceiling joists can come out, so get it right before quoting.
What the model code says
- A ridge board must be at least 1 inch nominal thick and at least as deep as the cut end of the rafter. (IRC 2021, Chapter 8)
Check which code edition your building department enforces for ridge board before you quote.
Work it out
- Licensing: Roofing license rules by state
- Tools, templates and guides: Free roofing resources
Sources: 2021 International Residential Code, Chapter 8, Roof-Ceiling Construction (ICC). Checked October 9, 2026.