What collar tie means
A collar tie is a horizontal board that connects opposing rafters in the upper part of the roof, near the ridge. It helps hold the rafters to the ridge in wind uplift.
Where it matters on a roofing job
Collar ties are not the same as rafter ties down at the wall plate, which stop the walls from spreading. Homeowners finishing an attic often want to remove ties for headroom; that is an engineering question, not a call to make on site.
What the model code says
- Opposing rafters at a ridge board are connected with a collar tie or ridge strap and may not be offset more than 1 1/2 inches. (IRC 2021, Chapter 8)
Check which code edition your building department enforces for collar tie 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.