How much bearing do floor joists and girders need at the ends?
At least 1½ inches of bearing on wood or metal, and at least 3 inches on masonry or concrete (IRC R502.6).
Floor joists, beams, and girders need a minimum end bearing of 1½ inches (38 mm) when they rest on wood or metal. When they bear on masonry or concrete, that minimum increases to 3 inches (76 mm).
The code also allows equivalent support: a 1-by-4 ribbon strip nailed into the adjacent stud, or an approved joist hanger. Where a member sits on masonry or concrete, the bearing must be direct or on a nominal 2-inch sill plate.
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Adopted edition and local amendments vary by city and county. Ask Donnie checks your jurisdiction and cites the exact adopted section.
Ask Donnie →General information based on the International Residential Code (a model code). This is AI assistance to verify — not legal advice. Confirm the adopted edition and any local amendments with your local building department (AHJ) and a licensed professional before you build.