Lump Sum Firm Price
By George Giannakakis · M.Arch · RLA300580 · HIA Industry Judge
Last reviewed: · How we research
Lump Sum Firm Price explained in detail
A contract where a builder agrees to complete a project for a fixed price, regardless of any changes in costs that may occur during the project. This gives the homeowner certainty on price, but builders typically include contingencies to cover their risk. Also known as a fixed-price contract.
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Frequently Asked Questions
Common questions about lump sum firm price
A fixed price (lump sum) contract means the builder agrees to complete your home for a set price. The price only changes if you make variations (changes) or if there are unexpected site conditions. Most project home builders in Australia offer fixed-price contracts.
Contract and legal information
Building contracts, dispute resolution, and consumer law are complex and vary by state and contract type. The information here is general in nature and may not apply to your situation. For advice about your specific contract, rights, or dispute, speak with a building lawyer, your state’s consumer protection body, or a licensed building consultant.
Cost figures are indicative onlyUpdated February 2026
All prices and cost ranges mentioned are approximate, based on Adelaide market conditions at time of writing, and may not reflect current pricing. Actual costs depend on your specific site, design, builder, materials, and market conditions. Project-specific quotes from qualified professionals are needed for accurate pricing.
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Verify against the binding rules in your state
BuildPilot is an independent home-build CoPilot - we publish guidance, we don't hold a building licence. Every Australian residential build must comply with the National Construction Code plus state-specific Acts and consumer-protection law. The authorities below are the primary sources of truth for the rules that actually apply to your project.
National
The primary national set of technical building standards that every Australian build must comply with. Volume 2 covers Class 1 & 10 buildings (most homes).
Specific material, product and method standards (e.g. AS 3700 masonry, AS 1684 timber framing) referenced by the NCC.
National peak body for residential builders. Publishes the most widely used home-building contracts and consumer guidance.
National peak body for general builders. Publishes commercial and residential contracts and industry guidance.
By state & territory
Links above open the public website of each authority. BuildPilot is not affiliated with these bodies and does not act on their behalf. Information on this page is general - check the current edition of the NCC and the relevant state Act for binding requirements.
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