In brief
I price my builds as a lump sum: the price is fixed in writing before construction starts and covers the scope we wrote down together. If steel gets more expensive along the way, or the work takes more days than I allowed for, that is my problem, not yours. The price does not come from a square metre: we start with a range, and the further we get in our conversations and in the concept design, the narrower it becomes — when the concept is ready, the price is final. One thing changes it: your decision to change the scope, and you know what a change will cost and what it does to the schedule before you decide. We settle by stages, not up front.
How are you supposed to know what this house should cost
With clients who build residences, I rarely talk about whether they can afford the house. We talk about something else: how you are supposed to know what it should cost — and how you can be sure the figure in the contract is the figure you will actually pay. That second worry is, in my view, entirely justified, because the script has repeated itself for years: the starting price looks good, and a few months in the contractor starts explaining that things came up on site, that this was not in the quote, and that more money is needed.
The way I settle my builds comes directly from that worry. The price we sign is the price you pay — within the scope we wrote down together. If steel gets more expensive or the carpenter raises his rate, that is my problem. If the job took more hours than I counted, that is mine too. Counting the cost of a build is my trade, so I am the one who should carry the risk of having counted wrong — not you.
Where a price that does not change comes from
How can anyone give a fixed price for a house with a pool below the groundwater level, a car lift and a dozen or so separate installations, when it is precisely on projects like these that contractors run from fixed prices first? It can be done, but the final price needs three things. Before I describe them, let me say where such a price does not come from.
Not from a square metre. A per-metre price more or less works for a typical house, where cost really does grow with floor area. In a residence, the most expensive things have nothing to do with floor area: a pool costs what it costs in a bigger house and in a smaller one, and a car lift is the same. Two houses with the same floor area can carry completely different budgets, and we are not talking about a few per cent.
Nor does it come from a single figure given at the first meeting. At the first conversation you get a range, because you want to know straight away what order of magnitude we are talking about — and that is fair. The longer we talk and the more finished the concept is, the narrower that range becomes; the moment the concept is ready, the price is final. If someone gives you a binding figure for a residence after one conversation, it means they have not counted it yet.
The first thing is a feasibility study: ground and groundwater surveys, a review of the design to see whether it can be built the way it was drawn, and a close look at the special elements. Before I agree, I need to know that I will deliver the right result.
The second thing is complete documentation, at detailed-design level — with details, schedules and the clashes between building systems resolved. The permit set alone is not enough to price from. Why the permit design and detailed-design documentation are two different things is something I cover in my text on working with your architect.
The third thing is my own take-off and pricing — work I do in-house and that nobody sees. You do not receive an item-by-item cost estimate as in a public tender; you receive the price and a description of what is in it and what is not — and it is that description that decides whether, a year from now, we are talking about the build or about what was in the price.
Only after all that does the range close into a single figure that I can sign as fixed, because I know what is inside it.
Who pays for what
To leave nothing unsaid, let me go through it one by one: who pays for what. Rising material and labour prices during the build are on me — the price does not change. The same goes for work that turned out bigger within the same scope: that is what the take-off is for, and a mistake in my own take-off is my cost. An execution error is on my side too — the repair sits inside the contract price and we do not turn it into an amendment. Ground conditions are surveyed before the price: surveys do not erase the risk, but they let it be named and priced, and whatever genuinely cannot be foreseen is described separately in the contract before you sign it — so that you know on what basis it will be calculated, and how and when you will be told the amount. That leaves one thing that can move the figure: your decision to change the scope. It is covered below.
And one more thing, because it is a common misunderstanding: a lump sum does not mean paying up front. I am not saying advance payments are wrong. They are necessary, because nobody serious will lay out large sums for materials on your build blind. But a build runs in stages — so the settlement should run in stages too. On my builds it does.
You change your mind mid-build
A residence takes about two years to build. In that time you will see something at a friend’s house, something in a hotel, something online — and part of it you will want in your own home. There will be changes; I have not seen a build without any. What matters is only how they enter the build.
On my builds, changes go through one route: you raise the change, I check what it touches — the structure, the installations, the schedule — and before anything is built, you are told what it will cost and what it does to the schedule. You decide in writing, and at the end we update the documentation, so that six months later nobody is building from an old drawing. Changes do not get in over the phone on my builds, and there is no situation where you learn the price of a change from an invoice. The whole procedure — who pays for what, and how to tell when a change has stopped being worth it — I set out in a separate piece on changes during construction.
Why the procedure? Because in a residence, hardly any change is as small as it looks. One partition wall can touch the structure, the underfloor heating, the automation and the lighting at once. Moving it on a drawing is hours of a designer’s work; moving the same wall in a finished house means demolition, reworked services and plastering done over. The later a change comes, the more work it drags behind it — which is why every change price also comes with its cost in time. Sometimes that is what decides.
The procedure has one more effect: some changes simply fall away once the full price is on the table. Not because someone cannot afford them — simply, at the full cost and the full time, some things stop making sense.
What this price does not cover
Let me also say where that fixedness ends — so you do not hear it for the first time at the contract table.
Scope changes at your request. That is the one door left open on purpose, and the rules are above: a price and your written decision before anything is built.
Things outside the written scope. The boundary of the price runs exactly where the documentation and the standard description end. In my experience, disputes over what was in the price are almost never disputes about bad faith — they are disputes about scope that nobody bothered to pin down while there was still time. That is why we write the scope down before the contract, tediously and precisely.
What to ask any contractor who promises a fixed price
Ask these questions of anyone — me included. The answers in this text will not change:
- What was the price built on — a take-off from detailed-design documentation, or square metres and experience?
- What exactly defines the scope: which documents, which standard description, what sits outside the price?
- How do changes enter — is every one priced before the work is done, and do you get the impact on the schedule together with the price?
- Who pays for repairing an execution error?
- How do payments run — after accepted stages, or by calendar dates?
Two answers should put you on alert: a promise that changes will somehow be sorted out, and pressure to sign quickly. Both mean the same thing — something was left unsaid and will come up during the build.
Questions about working with me — from budget, through how the first conversation runs, to the settlement model — I answer in the Questions section.
Frequently asked questions
Can a lump-sum price rise at all?
Not because of my costs — more expensive materials, higher rates or more work within the same scope do not change the contract figure. The one real reason is you changing the scope, and you know the price of the change before the decision is made.
Under a lump sum construction contract, can the contractor demand extra payment for additional works?
For work that sits within the agreed scope — no. A lump sum covers what the documentation describes, including when the work turns out bigger than the contractor assumed. Extra payment applies only to works that really do sit outside the scope — and with me it is preceded by a price and your written decision.
When will I know the price?
At the first conversation you get a range. The longer we talk and the more finished the concept is, the narrower it becomes — the moment the concept is ready, the price is final.
Will I get a detailed cost estimate?
No. The take-off and the pricing are my in-house work. You receive the price and a description of the scope — what is in the price and what sits outside it — and that is what we base the contract on.
If you are thinking about a residence and want to know what its fixed price would look like — you are welcome. Let’s talk about your project.