Ledger board
The board that bolts an attached deck to the house — the single most safety-critical connection on the whole structure.
The ledger board is the horizontal board fastened to the house that carries one entire edge of an attached deck. Because so much load runs through it, a failed ledger is behind a large share of deck collapses — usually because it was nailed instead of **bolted or lag-screwed**, or because missing [flashing](/glossary/flashing) let water rot the connection where the deck meets the wall. Inspect it every year: look for rust, gaps, movement, or rot, and confirm there's flashing shedding water away from the joint. If it's loose or rotted, keep people off the deck and call a pro — see [how to maintain a wood or composite deck](/guides/how-to-maintain-a-deck).