The fixed-price trap: why a locked price doesn't mean a safe build
A fixed-price contract feels like the safest thing you'll sign. It's often the most misunderstood. The number on the front page is real — but a build has more than one number, and the one that's fixed is rarely the one that decides what you actually pay. Provisional sums, prime-cost items and variations sit inside almost every fixed-price contract by design, and every one of them is an estimate that can move up.
That's the trap. "Fixed price" describes the contract, not the project. It locks the parts the builder can see clearly today and leaves placeholders for the parts nobody has fully resolved yet — and those placeholders are where a build quietly grows.
What a Locked Price Actually Locks
Read past the headline figure and a fixed-price contract is usually two documents in one. There's the fixed portion: the work that's fully drawn, specified and costed. And there's the soft portion: provisional sums for work that isn't resolved yet, and prime-cost allowances for finishes you haven't chosen. Stone, joinery, tapware, tiling — the items that define a luxury result are often the ones carrying a placeholder number, because the real one can't be set until the selection is made.
The contract is honest about this. The problem is that the headline price isn't, because it presents a single confident figure over the top of a stack of allowances that were only ever educated guesses.
Why the Number Moves
A fixed price moves for two reasons, and neither of them means anyone did anything wrong.
The first is selection. A prime-cost allowance is a budget line, not a commitment to a product. Choose stone above the allowance — as most people do, because the allowance was set low — and the difference is yours. It arrives as a variation, and it's entirely legitimate.
The second is discovery. A provisional sum covers work that couldn't be fully priced when the contract was signed, because it depended on something no one could see yet. When the real scope surfaces, the allowance trues up to it. Again, correctly, and again, upward.
Neither is a failure of the contract. Both are the contract working exactly as written — which is precisely why a locked price gives so little protection on its own.
What a Safe Price Looks Like
A price is only as safe as the detail underneath it. A figure built on thin allowances and generous provisional sums will hold on paper and move in reality. A figure built on resolved scope and honest allowances is the one that actually lands where it started.
So the question to ask before you sign isn't "is the price fixed?" It's "what is this price built on?" — how much is genuinely costed, how much is placeholder, and how far the real numbers are likely to travel from the ones on the page.
At Albert Living, this approach is part of the broader philosophy behind Albert AI—helping homeowners understand what they're really signing before construction begins. Albert AI Price reads the number behind the number, separating genuinely fixed costs from allowances waiting to move, so the price you sign is the price you're far more likely to finish on.
See What Your Fixed Price Is Really Built On
Understand the number behind the number before committing to your project.
