Timber jetty repair & replacement on the Gold Coast.

Repair scope ladder.

• Spot board replacement (2–6 boards): Replace individual cracked, split or rotted deck boards. F17 hardwood matched to existing species and stain. $400–$1,200 per board including labour. Typical project: $1,500–$5,000.
• Half deck replacement (40–60% of boards): When the deck is patchy and the board lifecycle has staggered out, full half-deck strip-and-replace is often cheaper than serial repair. $5,000–$12,000.
• Full deck replacement on retained piles: Strip all decking + bearers + stringers, retain pile network if marine-borer-survey passes, rebuild structural framing + deck in F17 hardwood. $15,000–$30,000. 5–10 day project.
• Pile-cap repair (where pile is sound but cap has split): Replace pile-cap timber, re-bolt bearers, sister-stringer if needed. $1,500–$3,500 per cap.
• Stringer / bearer replacement: When the horizontal structural member has rotted at the pile-cap joint. $2,500–$7,000 per bearer including disassembly and re-fix.

F17 hardwood species — which we use when.

• Turpentine (Syncarpia glomulifera): The gold standard for Gold Coast marine timber. Natural marine-borer resistance built into the timber chemistry. Underwater service life 40–60+ years. Above-water 60+ years. Cost: ~$4,500–$8,500/m³. Premium structural and deck choice.
• Ironbark (Eucalyptus paniculata / E. crebra): Extremely dense and hard, but limited marine-borer resistance below water. Above-water 30–40 years, underwater 25–35 years. Cost: ~$3,500–$5,500/m³. Excellent deck and bearer choice, less ideal for piles.
• Jarrah (Eucalyptus marginata): Premium WA hardwood with decent marine-borer resistance. Above-water 30–45 years, underwater 20–30 years. Cost: ~$4,000–$6,500/m³.
• Spotted gum (Corymbia maculata): The most affordable F17 hardwood. Limited marine-borer resistance without treatment. Above-water 25–35 years, underwater 15–25 years (treated only). Cost: ~$2,800–$4,200/m³. Good budget choice for deck-only above-water work.

Marine borer (Teredo) attack assessment — the critical check.

Every jetty-repair quote starts with a marine-borer attack survey on the existing pile network. We probe each pile at the waterline and 50–100mm below it with a calibrated steel probe; sound timber resists, hollowed timber gives way. We measure pile diameter at the tidal-zone splash line and compare to the original above-water diameter — any 10%+ reduction is significant. We sound-test each pile by tapping (hollow piles have characteristic dead sound). We photographically document every pile. If marine-borer attack is structurally significant on more than 30% of the pile network, repair isn’t the right call — we recommend rebuild instead and provide a no-charge revised quote.

Hardware spec — 316 stainless is non-negotiable.

All fixings on Gold Coast canal jetties must be 316-grade marine stainless. 304-grade (cheaper, common on inland work) rusts within 2–3 years in canal salt-spray and the rust bleeds through the timber leaving permanent stains. Galvanised steel breaks down in 5–8 years. We use 316 throughout: deck screws, coach bolts, structural threaded rod, joist hangers, balustrade brackets, ladder treads. The hardware premium is ~15–25% but the lifecycle cost is dramatically lower.

Timeline for typical repair scope.

1. Day 1 (am): Demolition of old timber, marine-borer probe of pile network, deck-board strip.
2. Day 1 (pm): Pile-cap inspection and remediation if needed.
3. Day 2–3: Bearer / stringer replacement if scope includes.
4. Day 3–5: Decking install, hardware fitting, edge finishing.
5. Day 5 (pm): Oil / stain (if hardwood deck), final clean, handover.