How to Replace Rotted Wood Deck Boards
Time required: 2-3 hours · Difficulty 2/5
Soft, spongy, or rotted deck boards are a fall-through hazard, especially near stairs or the rail line. If the rot has spread into the joists or ledger board underneath, stop — that's a structural repair for a licensed contractor, not a board-only DIY swap.
Est. DIY Parts: $25 - $45 · Pro Service: $200 - $400 · Est. Savings: $160 - $370
* Estimates based on regional/national contractor rate benchmarks. Actual part prices vary by brand and retailer.
Parts & Tools You'll Need
- 5/4 in. x 6 in. Pressure-Treated Deck Board
- Exterior Composite/Deck Screws (Coated, 1 lb Box)
- Circular Saw
- Pry Bar / Flat Bar
- Drill/Driver
Step-by-Step Manual
- Confirm the joists underneath are solid Probe the joists beneath the bad board with a screwdriver — if they're soft or crumbling, stop and call a contractor; this guide covers board-only replacement.
- Remove the fasteners Back out all screws or pry up nails securing the rotted board to each joist below.
- Pry out the old board Work a flat pry bar under the board at each joist and lift it free. Remove any leftover fasteners from the joists.
- Cut the new board to length Measure the gap and cut your new pressure-treated board to match, squaring the ends with a speed square.
- Fasten the new board Set the new board in place with consistent gaps matching your neighboring boards, then drive deck screws into each joist, two per joist.
- Seal and blend (optional) Apply a matching deck stain or sealer once the board is installed so it weathers evenly with the rest of the deck.