What anchor bolt means
An anchor bolt is a bolt set in concrete, usually as it is poured, that ties the sill plate or a post base to the foundation.
Also called J-bolt.
Where it matters on a carpentry job
Missing or misplaced anchor bolts are found at framing inspection, and drilling in epoxy anchors after the pour costs time. Lay out the bolts with the forms, not after.
What the model code says
- Sill plates are anchored with at least 1/2-inch anchor bolts no more than 6 feet apart. (IRC 2021, Chapter 4)
Check which code edition your building department enforces for anchor bolt before you quote.
Work it out
- Free calculator: Concrete block calculator
- Tools, templates and guides: Free carpentry resources
Sources: 2021 International Residential Code, Chapter 4, Foundations (ICC). Checked October 9, 2026.