What ceiling joist means
Ceiling joists span between walls to carry the ceiling below and often tie the bottoms of the rafters together so the roof cannot push the walls out.
Where it matters on a carpentry job
Removing ceiling joists for a vaulted ceiling changes how the roof holds itself up. It needs a ridge beam or other design, which is engineering work, not a demo day decision.
What the model code says
- Rafter and ceiling joist ends need at least 1 1/2 inches of bearing on wood or metal. (IRC 2021, Chapter 8)
Check which code edition your building department enforces for ceiling joist before you quote.
Work it out
- Free calculator: Framing calculator
- Tools, templates and guides: Free carpentry resources
Sources: 2021 International Residential Code, Chapter 8, Roof-Ceiling Construction (ICC). Checked October 9, 2026.