Decking Mistakes That Lead to Premature Failure

Intermediate Level

Why decks fail early: ledger failures, wrong fasteners, missing flashing, inadequate ventilation.

Materials Needed

Note

Standard galvanized with ACQ lumber is the #1 cause of premature deck hardware failure. Use G185 HDG or stainless.

Note

Leave 1/8"–3/16" gaps between deck boards. Tight boards trap water and accelerate rot.

Nailed Ledger Boards

Nailing the ledger is the primary cause of deck collapses. IRC requires 1/2" lag screws or through-bolts. No exceptions.

Missing Flashing

The ledger traps water against the band joist without flashing. Self-adhered membrane behind, Z-flashing on top.

Wrong Fasteners for Treated Lumber

ACQ is 5× more corrosive than old CCA. Every fastener touching treated wood: HDG (G185 min) or stainless.