Fence and deck repair: when to fix vs replace, cost, and finding the right pro

For both fences and decks, the posts (the vertical members anchored in the ground) are the make-or-break component. Boards rot — that's expected and replaceable. But when posts rot, the whole structure becomes unstable and replacement is the only durable fix. Rot starts at the ground line where moisture meets oxygen — typically year 8-15 for pressure-treated lumber, year 4-7 for cedar, year 2-4 for untreated wood. Steel posts (galvanized or powder-coated) and concrete-encased posts last 30+ years. The diagnostic: push hard against a post at the top — if it moves more than 1-2 inches, the post is going. Probe the wood at ground line with a screwdriver — if it sinks in, rot is established.

Repair makes sense when: (1) under 30% of posts are compromised; (2) the existing post material is what you'd use for replacement (don't replace cedar with cheap pine); (3) the fence design and height still work for your needs. Replacement makes sense when: (1) 30%+ of posts are rotting (you'll repeatedly chase the next failure); (2) the existing fence is undersized (you wanted 6 ft but have 4 ft) or wrong style (you want privacy but have picket); (3) the existing fence is over 15 years old and showing systemic wear, not just spot damage. Cost-wise, repair runs $200-$600 per fence section, $500-$1,500 per gate. Replacement runs $25-$60 per linear foot — $3,000-$7,500 for a typical 100-150 ft yard.

Deck repair scales similarly. Replacing 5-15 boards: $200-$800. Replacing 1-3 joists (the structural framing under the deck): $400-$1,500 — but this is harder, requires removing the deck boards above. Adding a railing section: $300-$1,000. Full deck replacement: $30-$60 per sq ft. A 200 sq ft deck (10×20 ft) runs $6,000-$15,000 to replace. The tipping point: if joists or ledger board (the structural piece attached to the house) are compromised, replacement is the call. If only deck boards are aging while structure is solid, board-replacement repairs work for 5-10 more years.

Wood vs composite is the big choice. Pressure-treated pine: $25-$40 per linear foot installed; lasts 15-20 years; needs annual stain/sealing; cheapest upfront. Cedar: $35-$55; lasts 20-30 years; less staining required; mid-tier. Composite (Trex, TimberTech): $50-$90; lasts 25-30 years with no staining; premium. Aluminum/steel posts: $50-$100 per post; last 30+ years; pair with wood or composite boards. Over 25 years, composite is roughly cost-neutral with wood once you factor in stain cycles. Composite wins if you hate maintenance; wood wins if you like the natural look and don't mind staining every 2-3 years.

Five things that drive fence/deck quotes higher: (1) buried debris under the post location requires excavator instead of post-hole digger; (2) the existing concrete footings are bigger than expected and need to be broken out; (3) HOA approvals require specific materials or styles that cost more; (4) underground utilities (irrigation, gas, electrical) need locating and avoiding — call 811 always; (5) slope or grade changes require step-down sections or grading work. A reputable contractor walks the site before quoting and explicitly notes "if X, then Y" pricing for known unknowns.

DIY is realistic for: (1) replacing 5-10 deck boards on a flat surface — half-day project, $200 in materials; (2) staining or sealing existing wood — half-day to full-day, $50-$200 in materials; (3) replacing single fence boards or pickets — easy carpentry. DIY is NOT realistic for: post installation (requires concrete and proper depth), gate hanging (requires alignment skill), structural joist replacement, anything over 6 feet tall (safety + permit issues), or full deck builds (multi-day project requiring precise framing). The cost of DIY mistakes on structural work is often more than the labor savings.