Deck Repair Cost Calculator
Deck repairs are priced by the piece, not by the square foot: so many boards, so many joists sistered, a post or two, a run of railing. Enter what needs fixing and this adds it up, then compares the total with the cost of a new deck the same size, because once repairs pass about half the price of replacement most homeowners are better off rebuilding.
What you'll need
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How deck repairs are priced
Nobody quotes a deck repair by the square foot. A carpenter prices the pieces — boards, joists, posts, railing sections, treads — plus the time to take the old ones out and haul them away, and most have a minimum charge for a small job because the drive and set-up cost the same whatever the size. The calculator does the same: enter a count for each item and it totals them at planning rates, then sets the total beside the cost of a brand-new deck the same size.
Typical repair prices per item
| Repair | Contractor, installed | DIY materials |
|---|---|---|
| Pressure-treated deck board (to 16 ft) | $45 – $85 | $18 – $30 |
| Composite / PVC deck board | $90 – $160 | $50 – $90 |
| Sister a joist | $150 – $350 | $35 – $70 |
| Replace a post | $300 – $700 | $60 – $140 |
| Railing, per linear foot | $30 – $60 | $12 – $25 |
| Stair tread | $40 – $80 | $15 – $35 |
| Re-flash and re-bolt ledger | $800 – $2,000 | $150 – $350 |
Repair or replace: the half-price test
A common rule of thumb is to get a replacement quote once repairs reach about half of what a new deck would cost. The reasoning is that the parts you are not repairing are usually the same age as the ones that failed. If three joists have rotted at the top, the others are rarely far behind, and paying for new boards on tired framing buys only a few years. The calculator shows repairs as a percentage of replacement and flags anything over 50%.
Age matters too. A pressure-treated deck past 15–20 years, or any deck built before modern ledger flashing and lateral load connectors were common, deserves a structural look before you spend on cosmetics. Our repair or replace guide and the deck safety inspection checklist walk through what to check.
Where the hidden costs are
- Rot you cannot see. Probe joist tops, post bases and the ledger with a screwdriver. If it sinks in, the repair list grows.
- Colour match. New pressure-treated boards are green or brown next to grey ones; composite colours change between production runs. Budget for staining or a few extra boards.
- Code upgrades. Replacing a ledger, post or railing can trigger current code — joist hangers, lateral load devices, 36 in guards with 4 in openings.
- Permits. Structural repairs often need one; board swaps usually do not. See the deck permit cost calculator.
Related calculators
If the answer is "replace", price it with the deck replacement cost calculator or new boards on the old frame with the deck resurfacing cost calculator. Tear-out on its own is covered by the deck demolition cost calculator. If the boards are sound but tired, the deck refinishing cost calculator is the cheaper route.
Get the Smart Decking Calculator app for Android
Estimate decks on the go, save projects, and share them with contractors.
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Frequently asked questions
- How much does deck repair cost?
- Most repairs are priced by the piece. As a planning range a contractor charges roughly $45–$85 to replace a pressure-treated deck board, $90–$160 for a composite one, $150–$350 to sister a joist, $300–$700 to replace a post, $30–$60 per foot of railing and $800–$2,000 to re-flash and re-bolt a ledger — plus a minimum call-out charge.
- When should I replace my deck instead of repairing it?
- A common rule of thumb is to price replacement once repairs reach about half the cost of a new deck, or when the framing itself — joists, beam, ledger or posts — is rotting in more than a few places. New boards on tired framing only buy a few years.
- Can I replace just a few deck boards?
- Yes. Pull the damaged boards, check the joist tops underneath, and fit new boards the same thickness. New wood will look different from weathered boards until it greys or is stained; composite colours drift between production runs, so buy from the same line if you can.
- Is deck repair covered by homeowners insurance?
- Sudden damage — a fallen tree, a storm, a fire — is often covered. Rot, insect damage and wear are maintenance and usually are not. Check your policy and photograph the damage before you start.
