A well-built deck should last 20 to 30 years, but only with the right maintenance schedule for the material. Here's what each type actually needs.
Pressure-treated pine decks need annual inspection and sealing every two to three years with a quality penetrating oil-based sealer. Skip the sealer and boards will cup, split, and check within five to seven years. Sweep debris off regularly — decomposing organic matter accelerates rot at the joist tops.
Cedar decks are more forgiving but benefit from annual oiling with a cedar-specific oil (Sansin, TWP, or Cabot). Cedar left unfinished will silver to a nice patina but wears faster on the surface. If you like the warm honey tone, oil it annually.
Composite decks (Trex, TimberTech, Fiberon) need almost nothing — periodic soap-and-water wash, and occasional deep clean with a composite-safe cleaner if you get grease or berry stains. Do not power wash on high pressure, do not use bleach.
Every year, regardless of material: inspect all railings for wobble, check ledger board bolts and flashing where the deck meets the house, look for rot at post bases, verify joist hangers are still tight and rust-free. These are safety items — call a pro if anything looks marginal.