Residential Building Inspector B1Public Safety and Special ConstructionHard
An inspector is evaluating a deck that is attached to a dwelling. What is the minimum required size for a deck ledger board bolt, assuming the ledger is attached to a band joist with solid blocking between joists?
- A3/4 inch diameter
- B1/2 inch diameter
- C5/8 inch diameter
- D3/8 inch diameter
Show answer & explanationAnswer & explanation
Correct answer: B. 1/2 inch diameter
IRC Table R507.2.2(1) specifies that the minimum diameter for bolts or lag screws used to attach a deck ledger to a band joist is 1/2 inch. This is crucial for ensuring the structural integrity of the deck connection.
Why the other options are wrong
- A. This diameter is significantly larger than required and generally unnecessary for typical residential deck ledgers.
- C. This diameter is larger than required but would be acceptable.
- D. This diameter is too small for a ledger board bolt and would not meet code requirements.
Deck Ledger Bolt Diameter
The bolts or lag screws connecting a deck ledger board to the house band joist are critical structural fasteners. Their size and spacing are regulated to safely transfer the deck's load.
- Connects deck ledger to dwelling band joist.
- Minimum 1/2 inch diameter for bolts/lag screws.
- Spacing depends on joist size and span.
Memory trick: Deck ledger, half-inch bolt, for a connection that won't jolt.