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An interactive comparison platform for home buyers to evaluate builders, plans, and inclusions in their region side-by-side.

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Pricing

Contract Type

The type of contract your builder offers — fixed-price, cost-plus, or prime cost/provisional sum — fundamentally determines your budget certainty. Understanding which contract type you're signing is more important than any individual inclusion on the list.

Builders Include Standard

Offer as Upgrade

Do Not Include

What is it?

Contract type refers to the pricing structure of your building agreement. A fixed-price contract locks in the total cost (barring variations you request). A cost-plus contract charges actual costs plus a builder margin. A prime cost (PC) and provisional sum (PS) contract includes estimated allowances that can rise or fall during construction.

Why buyers compare it

Fixed-price contracts eliminate the biggest source of budget blowouts
PC and PS allowances are the most common cause of post-contract price increases
Two builders with the same headline price can have very different contract risk
Generous PC/PS allowances are a red flag — they suggest the quote is too low

Is it worth upgrading?

You want absolute budget certainty before construction begins

Your site has known ground conditions that could trigger variations

You're risk-averse and want to avoid cost surprises mid-build

Your builder offers a genuine fixed-price contract with no provisional sums

You have contingency funds set aside and are comfortable with some flexibility

Questions to Ask Your Builder

Is the contract fixed-price, or does it include provisional sums and prime costs?What are the specific PC and PS allowances, and are they realistic?What builder margin is applied to variations and cost-plus items?Is there a cap on how much provisional sums can increase?What happens if PC or PS items come in under allowance — do you get a credit?Are site costs fixed or provisional?

Contract Type — Typical Costs

Fixed-Price

$0 variation risk

All costs locked in — best for budget certainty (if allowances are realistic)

PC + PS Contract

$5,000 – $30,000+ variation risk

Prime costs and provisional sums may rise during construction

Cost-Plus

Highest risk

Actual cost plus builder margin — open-ended, hard to budget

Compare My Build Tip

Ask for a full breakdown of every PC and PS item. If the tile allowance is $35/m² but realistic tiles cost $70/m², that's a hidden cost blowout waiting to happen. The quality of the allowances matters more than the headline price.

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Full breakdown of common upgrade costs across all categories in Australian home builds.

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The essential checklist of what to compare between builders before you sign a contract.

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Related: Pricing

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