Austek Home Improvements | Patios, Pergolas & Carports Sydney — Decking in Baulkham Hills

A basic treated pine deck (20m²) costs $4,000–$8,000 installed. Hardwood decking (Merbau, Spotted Gum) costs $6,000–$15,000 for the same size. Composite decking (Trex, Millboard) costs $8,000–$18,000 — more expensive upfront but lower lifetime maintenance cost. Elevated decks cost significantly more due to structural requirements.

Decks over 1m above ground, attached to the house, or exceeding area thresholds (varies by state and council) require a building permit. In most states, a ground-level deck under 1m high with area under 10–18m² is exempt. Decks in bushfire-prone areas require BAL-rated materials. Always check with your council or building surveyor before starting.

Hardwoods: Merbau (durable, affordable, reddish-brown), Spotted Gum (beautiful grain, extremely durable), Blackbutt (light blonde, durable). All are rated Class 1–2 for above-ground durability. Treated pine is budget-friendly but requires regular oiling. Composite decking (timber and recycled plastic) has lowest maintenance but looks less natural.

Merbau and most hardwood decks need oiling every 12–18 months to maintain appearance and UV protection. Treated pine needs sealing or staining every 12 months. Oil your deck when water no longer beads on the surface. Clean thoroughly before re-oiling. Composite decking requires only cleaning — no oiling needed.

Composite decking is made from a blend of recycled wood fibre and plastic — it won't rot, splinter, or need oiling. Brands like Trex, Modwood, and Millboard cost $180–$400/m² installed vs $120–$250/m² for hardwood. For families with children (no splinters), pool decks (moisture-resistant), and those who prefer low maintenance, composite is worth the premium.