When you receive paperwork from a builder, the words "quote" and "estimate" are sometimes used interchangeably — but they have very different meanings for your wallet. In New Zealand, a fixed-price contract locks the builder into a set price, while an estimate is an educated guess that can change as work progresses. Knowing which one you have before you sign is one of the most important steps in any building project.
What Is a Fixed-Price Quote?
A fixed-price quote (sometimes called a lump-sum contract) means the builder agrees to complete a defined scope of work for a specific dollar amount. Provided the scope doesn't change, you pay that amount — no more. This gives you certainty for budgeting and is common for well-defined projects like a new deck, bathroom renovation, or house extension.
Key features of a fixed-price quote:
- A single total price is clearly stated
- The scope of work is described in detail
- Variations (changes to the scope) are handled through a separate, written variation order with an agreed price before work begins
- The contract will usually say words like "fixed price", "lump sum", or "contract sum"
What Is an Estimate?
An estimate is an approximate figure based on the builder's best assessment at the time. It is not a guarantee. The final cost can be higher (or occasionally lower) depending on what is discovered once work starts — for example, rotting framing hidden behind cladding, or fluctuating material costs.
Estimates are common when:
- The full scope is unclear at the outset (e.g., a renovation where walls haven't been opened yet)
- The project involves significant unknowns (e.g., ground conditions for a foundation)
- The builder is pricing on a cost-plus or time and materials basis
How to Tell the Difference on Paper
The single most reliable way to know which type you have is to read the document carefully. Here's a quick comparison:
| Feature | Fixed-Price Quote | Estimate |
|---|---|---|
| Language used | "Fixed price", "lump sum", "contract sum" | "Estimate", "approximate", "budget figure" |
| Price certainty | Yes — price is binding | No — price can change |
| Scope of work | Detailed and specific | May be general or provisional |
| Variations | Require written sign-off | May be absorbed or added informally |
| Risk of cost overrun | Builder carries the risk | Homeowner carries the risk |
If the document uses vague language or doesn't clearly state "fixed price", ask your builder in writing before signing anything.
Watch Out for These Common Traps
Provisional Sums
Even a fixed-price contract can include provisional sums (PS) — placeholder amounts for items not yet fully specified, such as kitchen joinery or floor tiles. These are not fixed and will be adjusted once the actual cost is known. Make sure you understand which line items are provisional and budget conservatively for them.
Prime Cost Items
Similar to provisional sums, prime cost (PC) items are allowances for fittings or materials you'll choose later (e.g., tapware, light fittings). The final cost depends on what you select.
Scope Creep
Even with a fixed-price contract, costs can rise if you change your mind or request extras. Always insist on a written variation order with a price before agreeing to any changes.
What Should a Good Building Contract Include?
MBIE Building Performance recommends that residential building contracts clearly set out the price type, payment schedule, scope of work, and how variations are handled. For projects over $30,000 (including GST), builders are legally required under the Construction Contracts Act 2002 to provide a written contract. Even for smaller jobs, a written agreement protects both parties.
A solid contract should include:
- Whether the price is fixed or an estimate
- A detailed scope of work and specifications
- A payment schedule (avoid paying large deposits upfront)
- How variations are agreed and priced
- A timeframe for completion
- Dispute resolution process
BRANZ and Consumer NZ both offer useful guidance on understanding building contracts and your rights as a homeowner.
Building Consents and Licensed Builders
If your project requires a building consent (check with your local council — some work is exempt under Schedule 1 of the Building Act, but always confirm), the contract should also reference who is responsible for obtaining the consent and associated fees. These costs should be clearly itemised.
For restricted building work — such as structural work, weathertightness, and certain other elements — the work must be carried out or supervised by a Licensed Building Practitioner (LBP). Always check your builder's LBP licence status before signing a contract.
When to Call a Professional
If you're unsure about the terms in your builder's quote or contract, don't just sign and hope for the best. Consider:
- Asking your builder to clarify in writing whether the price is fixed or an estimate
- Getting a second quote from another builder to compare scope and pricing
- Consulting a lawyer who specialises in construction contracts for larger projects
- Contacting Consumer NZ or MBIE if you believe a builder has misrepresented their pricing
A reputable, qualified builder will be happy to explain their quote clearly. You can find experienced local builders on tradedirectory.co.nz who can provide transparent, detailed quotes for your project.
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