Set-price contracts, explained line by line
Why we say set price instead of fixed price, where allowances hide in other people's quotes, and the questions that expose a soft price before you sign it.
Why we say set price, not fixed price
Here is a piece of honesty most builders won't give you: no standard building contract in New Zealand is truly fixed, including ours, including the companies that advertise a "true fixed price". Every contract carries two clauses that can move the number. Earthworks sit under provisional sums, because nobody knows what is under the ground until it is opened up. And genuine cost shocks outside anyone's control can be passed through. The "fixed price" builders have those same clauses in their contracts.
So we say set price, because that is the truthful version: we set the price, and on our end it does not move. It changes only if you ask for a variation, or if something genuinely outside anyone's control turns up, like a buried rubbish heap where your foundations go. We would rather explain that on day one than have you discover it at the end of a build.
A builder can only set a price responsibly after doing the homework: walking the site, geotech, engineering and real quotes for the site works. That is why our set price comes after the free site evaluation and prelim works, not off a brochure.
Where soft quotes hide the risk
The polite word for a guess in a building quote is an allowance, or a PC (prime cost) sum, or a provisional sum. Each one says: we put a placeholder here, and you carry the difference if reality costs more. Common hiding places:
- Earthworks and retaining allowances on sloped sections
- Foundation allowances made before geotech exists
- PC sums for kitchens, bathrooms and appliances
- Driveway, landscaping and service connections listed as excluded
Questions that expose a soft price
Take any quote and ask: which lines are allowances or provisional sums, and what happens if they are not enough? Is the site work priced from an actual site visit and geotech, or estimated? Is the inclusions list complete enough that we could move in with nothing extra? A set price answers all three in writing.
The comparison worth making is never quote versus quote, it is scope versus scope. A cheaper number that excludes the driveway is not cheaper.
Quick answers
Two things can move it, and we name both up front: a variation you ask for, priced and signed before it happens, and something genuinely outside anyone's control, like what the digger finds under the ground. On our end, the price we set is the price we hold.
Usually scope: allowances instead of firm prices, and exclusions instead of inclusions. Ask both builders for their full inclusions list and the quotes converge quickly.
Keep going: The 2026 build price guide · Current house & land packages · Book a free site evaluation · or head back to the blog.
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Current build prices, land that’s worth a look, and lessons straight from the sites. Written by builders, not marketers.