9 Signs Your Deck Needs Repair (or Replacement)

Decks look simple, but they're structures that carry heavy loads high off the ground. Deck failures often happen without warning. Inspect yours at least once a year: ideally in spring, before the busiest season.

1. Soft or spongy wood

Probe boards, joists, and posts with a screwdriver, especially where wood meets the ground or stays damp. If the tip sinks in easily or the wood feels soft, you likely have rot.

2. A loose or wobbly railing

Push firmly on railings and posts. Any significant movement is a fall hazard. Railings should be securely fastened to the structure, not just to deck boards.

3. Problems at the ledger board

The ledger is the board that attaches the deck to your house. It's one of the most common points of failure. Look for gaps between the ledger and the house, rust stains, missing flashing, or signs of water getting behind it. A failing ledger is a job for a professional.

4. Rusted or missing fasteners and hardware

Check joist hangers, bolts, and screws for corrosion or missing pieces. Corroded connectors lose strength over time.

5. Cracked or split boards

Small surface checks are normal in wood. Deep cracks, splits through the board, or boards that flex noticeably should be replaced.

6. Leaning posts or sagging beams

Look at the deck from the side. Posts should be plumb and beams straight. Leaning, sinking, or sagging suggests footing or structural issues.

7. Wobbly or uneven stairs

Stairs take heavy use. Check stringers for rot, treads for cracks, and handrails for secure attachment.

8. Mold, mildew, and standing water

Slippery surfaces are a fall risk, and persistent moisture speeds rot. Improve drainage and airflow under the deck and clean surfaces regularly.

9. Insect damage

Small holes, sawdust-like debris, or tunnels in wood can indicate insects. Have it checked, as damage can be worse inside than it looks.

Repair or replace?

Surface boards are relatively easy to replace. But if the framing (joists, beams, posts, or ledger) shows widespread rot or damage, replacement is often safer and more cost-effective than patching. Decks built long ago may also not meet current codes for connections and railings.

When to call a professional

Call a licensed contractor or inspector if you find problems with the ledger, footings, posts, beams, or anything that affects how the deck carries weight. Don't put a hot tub, heavy planters, or a crowd on a deck you're unsure about.