What fireblocking means
Fireblocking is lumber, gypsum, mineral wool or approved sealant placed in concealed spaces, such as stud bays and around pipes, to slow fire spreading through them.
Also called fire blocking, draftstopping.
Where it matters on a carpentry job
Inspectors check fireblocking at framing inspection, especially where pipes and wires pass between floors. Carry the right foam or sealant and close every penetration before calling the inspection.
What the model code says
- The code defines fireblocking as materials installed to resist the free passage of flame to other areas through concealed spaces. (IRC 2021, Chapter 2)
Check which code edition your building department enforces for fireblocking before you quote.
Work it out
- Free calculator: Framing calculator
- Tools, templates and guides: Free carpentry resources
Sources: 2021 International Residential Code, Chapter 2, Definitions (ICC). Checked October 9, 2026.