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Methodology and sources

How we estimate deck building cost

Every estimate combines national unit costs with a local labor adjustment for your state. This page shows the formula, source inputs, limitations, and review notes behind the calculator.

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Methodology summary

Transparent formula

Quantities are driven by the deck's size, the decking material, whether it is ground-level or raised, and whether it includes a perimeter balustrade and a stair run; the project band is ±25%.

Regional labor only

Labor multipliers affect the labor share of each line item; materials stay nationally priced.

Clear limitations

These are planning estimates, not live contractor quotes or guarantees.

The formula

For each line item we multiply a quantity by a national unit cost, then apply a quality-grade factor. A regional labor multiplier is applied to the labor portion only; materials are priced nationally. We show the itemized result as a ±25% range.

National unit costs

Line itemNational unit costSource
Substructure (footings, beams & joists)$60.00 / m²source
Decking boards$170.00 / m²source
Build labor$88.00 / m²source
Railing$227.00 / m²source
Stair run$1,818.00 / m²source

Regional labor multipliers

Each state's labor multiplier is its private-sector all-industry full-time adult ordinary-time weekly earnings relative to the national private-sector mean, from ABS Average Weekly Earnings (November 2025, Table 14, by state) — used as a proxy for deck-building labour because Australia publishes no deck-builder/carpenter-by-state (ANZSCO 331212) earnings series in public form, and the private-sector cut strips out the public-service distortion that inflates all-industry figures in the ACT. Multipliers are bounded to a sane range and applied to the labor share of each line item, so materials stay nationally priced while labor tracks local wages.

Data vintage and limitations

Compiled June 2026 from public cost aggregators and government wage data. These are derived estimates, not live contractor quotes. Local prices vary with project complexity, access, and material availability; always confirm with a licensed contractor before budgeting.

Sources