Why This Matters
Ledger failure is the leading cause of catastrophic deck collapse. A deck pulling away from the house — even slightly — is an urgent safety matter that requires immediate professional evaluation.
What the Ledger Does
The ledger board transfers half the deck load — the weight of the structure, people, furniture, snow and wind — into the house framing. It is typically a pressure-treated board bolted or screwed to the house band joist or rim board. The ledger supports one end of every joist that runs perpendicular to the house.
Because the ledger is concealed behind siding and decking, problems can develop unseen for years. By the time visible signs appear — gaps between the deck and house, water staining on interior walls, or deck movement — the damage may already be extensive.
Three Things Every Ledger Needs
1. Correct Fasteners — Pattern, Type and Spacing
Ledger fasteners must be lag screws or through-bolts — never nails. They must be installed in a staggered pattern at specified spacing, typically every 16 inches. The fastener must penetrate through the ledger, through the sheathing and into the house band or studs. Screws into sheathing alone will not hold. Flashing must be installed before the ledger is fastened to the house.
2. Flashing — Top, Sides and Bottom
Flashing prevents water from entering the wall behind the ledger. The top flashing must extend up behind the siding and out over the ledger. Side flashing prevents water from running around the ledger ends. Bottom flashing is required when the ledger is over finished living space. Without proper flashing, water runs behind the ledger and rots the house band — a condition that can go unnoticed for years until the ledger pulls away.
3. Lateral Load Connectors
The ledger handles vertical loads — the weight pressing down. But decks also experience lateral loads — wind pushing sideways, people leaning on railings, and seismic forces. Lateral load connectors — typically metal tension ties that extend into the house floor system — prevent the deck from pulling away from the house. These are required by current building codes and are frequently missing on older decks.
Warning Signs of Ledger Problems
- Visible gap between deck and house — even 1/8 inch is concerning
- Deck movement or bounce near the house connection
- Water staining on interior walls or ceiling near the ledger location
- Rusted or corroded fasteners visible at the ledger
- Missing or damaged flashing above the ledger
- Ledger attached over siding rather than directly to house framing
- Nails used instead of lag screws or through-bolts
- No visible lateral load connectors
Have Your Ledger Evaluated
If you see any gap, movement or staining at the house connection, request an evaluation. Ledger problems do not improve on their own.
Request a Deck Evaluation