The 2026 Melbourne Decking Ledger: Cost Breakdown for Merbau, Spotted Gum, and Premium Hardwood

When planning an outdoor remodel in Melbourne, it’s important to strike a balance between market realities and lofty design goals. An outdoor deck is a high-value addition to your house, whether you are creating a coastal veranda in Mornington, expanding a family living room in Glen Waverley, or adding a courtyard gathering area in Northcote.

However, with ongoing shifts in trade labour rates, raw timber supply chains, and local compliance standards, estimating your project’s true cost requires up-to-date data.

In 2026, building a premium deck in Melbourne involves evaluating three major categories of native and imported hardwoods: accessible Merbau, architectural Spotted Gum, and high-density regional Australian hardwoods.

The actual per-square-metre ($m^2$) costs for materials, subfloor structural systems, professional trade labour, and long-term maintenance requirements in the local Victorian market are broken down in this guide.

1. Material Cost Breakdown: Per Square Meter & Profile Benchmarks

The base cost of your deck starts at the lumberyard. The price of hardwood decking boards can vary greatly depending on the width, thickness, profile and species selected.

In Melbourne, natural timber supply costs are measured both in linear meters ($LM$) and converted into square meters ($m^2$) for structural planning (including standard 5mm spacing gaps between boards).

Merbau Decking (The Accessible Hardwood Standard)

Due to its deep reddish-brown tones, good natural durability (Class 1 above ground), and affordable pricing, Merbau is still a popular imported hardwood option.

• 90mm Merbau Decking (19mm thickness):$7.50 to $10.50 per linear meter ($\approx \$75 \text{ to } \$105 \text{ per } m^2$ supply only).
• 140 Merbau Decking (19mm thickness):$12.00 to $16.50 per linear meter ($\approx \$80 \text{ to } \$110 \text{ per } m^2$ supply only).
• Best Suited For: Homeowners looking for a durable, budget-conscious merbau deck with a warm, classic dark color profile.

Spotted Gum Decking (The Architectural Standard)

Spotted Gum is a native Australian hardwood celebrated for its wavy grain, rich color range (from cream-straw to dark chocolate), high density, and natural BAL-29 fire resistance.

• 86mm Spotted Gum Decking Boards:$10.50 to $14.50 per linear meter ($\approx \$110 \text{ to } \$150 \text{ per } m^2$ supply only).
• 135mm/140mm Spotted Gum Decking Boards:$16.00 to $22.50 per linear meter ($\approx \$115 \text{ to } \$160 \text{ per } m^2$ supply only).
• Best Suited For:Modern architecture, bushfire-prone areas, property owners wanting a beautiful spotted gum deck.
• Alternative Premium Hardwoods (Ironbark, Blackbutt, Jarrah)

Other high-density native options for hardwood for decking deliver specialized performance and unique aesthetics across Victorian landscapes.

• Blackbutt&Silvertop Ash (86mm to 135mm):$\$110 \text{ to } \$155 \text{ per } m^2$ (supply only). Excellent for light, blonde, modern coastal aesthetics.
• Red Ironbark &Jarrah (86mm to 135mm):$\$130 \text{ to } \$180+ \text{ per } m^2$ (supply only). Ultra-dense Class 1 timbers built for extreme longevity.

2. Hidden Subfloor Infrastructure Costs

One common mistake in budgeting is to concentrate only on the top visible surface. An engineered foundation is necessary for a deck, and your framing materials have a significant impact on total square metre prices.

Subfloor Framing Material Options

• Treated Pine Framing ($50 to $80 per m²):Suitable for typical low-level residential areas. Provides a very economical material base with fast installation times.
• Galvanised Steel / Hardwood Frame ($110 to $170+ per m²):Necessary for sites with low ground clearance, damp soil, elevated multi-level structures or strict $BAL-29$ to $BAL-40$ bushfire compliance regulations.

Treated Pine Bearers and Joists

Using H3-treated pine for subfloor framing is the standard residential approach. It is cost-effective, durable, and easy for carpenters to work with on-site.

• Sub-frame Material Cost: Adds $50 to $80 per $m^2$ in raw structural timber and basic hardware.

Hardwood or Galvanised Steel Sub-frames

For low-ground clearance projects, moist soil sites or high-risk bushfire zones ($BAL-29$ or higher), a typical pine frame could not meet local building regulations or durability standards.

• Sub-frame Material Cost:Your overall material budget will increase by $110 to $170+ per square meter if you upgrade to treated hardwood or galvanised steel framing.

3. Trade Labour and Carpentry Rates in Melbourne (2026)

Melbourne’s on-site carpentry labour reflects the intricacy of installations, site access issues, and the current demand for trained labour. Certified carpenters typically price installation labour for conventional residential decks between $140 and $220 per square metre.

Key variables that adjust labour rates include:

• Site Access & Clearance:Manual material handling is necessary in inner-city areas (such as Fitzroy, South Yarra, or Carlton) with narrow side-alley access or steeply sloped properties, adding flat fee logistical surcharges ranging from $800 to $2,500.
• Fastener Style (Visible Screws vs. Concealed Clips):The typical method is to use marine-grade 316 stainless steel screws for top-down face screwing. Selecting hidden clip systems for a seamless finish adds $25 to $45 in labour and hardware expenses per $m^2$ and necessitates specialised board grooving and additional installation time.
• Old Deck Demolition & Disposal: Removing and disposing of an existing, rotted deck or concrete slab adds $30 to $60 per $m^2$ in trade labor and skip bin fees.

4. Complete Supply & Install Cost Summary (2026 Market Standard)

Complete turnkey bids in Melbourne often fall into one of three main pricing categories when raw hardwood decking timber, subfloor framework, fasteners, site preparation and certified trade labour are combined:

Budget / Mid-Range Tier: $320 to $420 per m²

• Materials: Standard 90mm merbau decking or treated pine framework.
• Installation: Basic rectangular layout, flat ground level, straightforward site access, visible stainless steel screws.

Architectural Premium Tier: $440 to $600 per m²

• Materials: Wide 135mm/140mm spotted gum timber decking or premium native hardwoods.
• Installation: Concealed fixing systems, multi-board picture-frame borders, steel/hardwood subfloor leveling, pre-oiling treatments, integrated low-voltage step lighting.

Custom / Complex Tier: $650 to $900+ per m²

• Materials: Ultra-dense Class 1 timbers (Red Ironbark), thick commercial board profiles, or custom steel sub-framing.
• Installation: Multi-level elevated structures, steep sloping sites, integrated bench seating, built-in planter boxes, strict BAL-40 bushfire compliance engineering.

5. Long-Term Maintenance and Initial Weathering Costs

Initial sealing and regular maintenance are necessary to safeguard your investment from Melbourne’s unpredictable weather. Rain and UV rays cause the natural wood fibres in hardwood decking boards to dry out, check, and turn silver-grey; therefore, they should never be left open.

• Initial Weathering & Cleaning: Within 4 to 8 weeks of completion, new timber must be washed with a specialized deck cleaner to remove natural mill glaze and surface tannins.
• Sealing & Oiling: Applying two initial coats of high-grade penetrating outdoor oil costs $15 to $25 per $m^2$ for DIY supplies, or $35 to $55 per $m^2$ if handled by a professional deck restoration trader.
• Regular Maintenance: To keep your spotted gum decking or merbau deck looking rich and stable, plan to apply a top-up coat of outdoor oil every 12 to 18 months. Regular maintenance cleaning can be easily done using a gentle soft-bristled broom and a specialised microfiber spray mop with a damp pad to sweep away outdoor dust and dirt without dulling your protective finish.

Frequently Asked Questions (FAQ)

1. Which timber is cheaper overall in Melbourne: Merbau or Spotted Gum?

Merbau is generally 20% to 35% cheaper than Spotted Gum in raw material costs.  In 2026, standard 90mm merbau decking supplies average $75 to $105 per $ m^2, whereas equivalent spotted gum decking boards range from $110 to $150 per $ m^2.  But labour costs to install both species are roughly the same.

2. How do I stop new Merbau decking from staining my concrete or pavers beneath?

During its initial exposure to rain, Merbau’s high concentration of water-soluble tannins leaches out as a dark, tea-colored liquid. Use a specialised tannin-removal cleaner immediately after installation, or select pre-cleaned or pre-oiled boards to avoid persistent staining on nearby sandstone pavers or light concrete. Make sure that any runoff water is directed away from light stone surfaces and toward drainage points.

3. Do I need a formal building permit to construct a residential deck in Melbourne?

In Victoria, under the Building Regulations 2018 enforced by the Victorian Building Authority (VBA), almost all deck installations require a formal building permit issued by a registered building surveyor. A permit is mandatory if the deck is attached to a house, exceeds 10$m^2$ in area, or sits higher than 800mm above ground level.

4. How much extra timber should I order to cover installation off-cuts and waste?

Ordering 10% to 15% more wood than your precise net square meter calculations is always a good idea. This waste margin takes into consideration angled off-cuts around posts or step details, board-end squaring, natural grain selection, and structural end-trims.

5. Can Spotted Gum decking be used in high-risk bushfire ($BAL$) areas in Victoria?

Yes. Spotted Gum is one of seven native Australian hardwoods naturally approved for building in bushfire-prone zones up to BAL-29 under AS 3959 without requiring additional chemical flame-retardant treatments. For extreme zones ($BAL-40$ or $BAL-FZ$), non-combustible sub-framing and specialized installation techniques are required.