In brief
I price my builds as a lump sum: the price is fixed in writing before construction starts and covers a precisely written scope. If materials get more expensive along the way, or the work takes more hours than I allowed for — that cost is on my side. A price like this is possible because it does not come from a price per square metre or from a conversation; it comes after a feasibility study, on complete documentation and item-by-item take-offs. One thing changes it: your decision to change the scope — and you see the price of every change, with its impact on the schedule, before you decide. You are buying the outcome, not a bill of my costs.
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 justified, because the script has repeated itself for years: the starting price looks good, and then it begins — “things came up on site,” “that wasn’t in the quote,” “we need to add.”
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. Steel gets more expensive, the carpenter raises his rate — my problem. The job took more hours than I counted — also mine. I take on the cost risk because counting costs is my trade.
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 difficult projects that contractors run from fixed prices first? A fixed price comes from preparation, not from courage. I have no other answer.
Let me start with where it does not come from. Not from a square metre. A per-metre price is guesswork — it 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.
It does not come from the first meeting either. A mechanic who quotes an engine rebuild over the phone, before anyone has looked inside, is not pricing — he is bidding. A house works exactly the same way. So before you hear any figure from me, three things have to happen.
First — a feasibility study. Ground and groundwater surveys, a build-oriented review of the design, a close look at the special elements. Before I say yes, I need to know I can deliver.
Second — complete documentation. At detailed-design level: details, schedules, 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.
Third — a take-off and an item-by-item price. The scope written out so that both sides know the same things about what is in the price and what is not. This part is tedious and nobody will ever admire it. I do it anyway.
Only after all that does the price stop being guesswork — and only then can I sign it as fixed, because I know what is inside it. For the same reason you will not hear it from me at the first meeting; you will get it in writing, before construction starts.
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. That leaves two things that can move the figure: your decision to change the scope — priced openly, before the work is done — and extraordinary situations on the scale of the whole market, which the law treats as a separate category. Both are covered below.
This split has a second side and I mention it right away: the price does not go down when I manage to build cheaper. If I buy materials well or organise the work better, the difference stays with me — just as a loss would be mine. A restaurant works the same way: you pay the menu price. Nobody comes over to charge you for butter that got more expensive — and nobody hands money back when the chef bought it cheaper. That is the deal.
And one more thing, because it is a common misunderstanding: a lump sum does not mean paying up front. We settle by stages — an instalment follows an accepted stage, and only an accepted stage. I have settled builds this way for years; I did not invent it for residences.
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. You get an itemised price and the impact on the schedule, before anything is built. You decide in writing. 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.
Why I do not settle on actual costs
There are models where you pay what the build actually cost: by measured quantities and market prices, or from the contractor’s bills with a margin added. I am not saying they are wrong — they have their uses, especially where the scope cannot be written down in advance. On a private residence I see two things about them that bother me.
First: the risk moves to you. Materials get more expensive — you pay. The work goes slower — you again. A contractor in that model has no great reason to fight for your budget, because it is not his budget.
Second: someone on your side has to check invoices, measurements and rates for two years, or the model stops being honest. I know people who truly enjoy that kind of control. The clients I build for usually want the opposite — to hand over the process and receive a finished house. A fixed price is part of that comfort.
What this price does not cover
Let me also say where “does not change” 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. That is why we write the scope down before the contract, tediously and precisely. Prevention first.
Situations the law treats as extraordinary. A fixed price works within normal, foreseeable business risk — that is also how Polish case law describes it. Exceptions exist, but they are narrow (ordinary inflation is not enough). I am not a lawyer and I will not tell you exactly where those lines sit — that is what your lawyer is for at the contract stage, and an honest contract simply spells those situations out.
And one reservation to close: you will not get a fixed price from me without the study and the documentation. If someone hands you a binding figure for a residence after one meeting, it means something was left uncounted — and in six months you will hear that “things came up on site,” and you are back in the script from the top of this text.
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 does the price come itemised, with the impact on the schedule?
- Who pays for repairing an execution error?
- How do payments run — after accepted stages, or by calendar dates?
Three answers should put you on alert: “we’ll sort it out somehow” about changes, a single figure with no breakdown, and pressure to sign quickly. Each of them means 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, after an open price and your written decision. Beyond that there remain extraordinary market-scale situations and changes forced by regulations — the law treats them restrictively, and an honest contract describes them.
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.
If the risk is on the contractor, what happens when he builds cheaper?
The difference stays with me — just as a loss would be mine. A lump sum works both ways: an agreed figure for an agreed outcome. Without that symmetry, no contractor could honestly carry the risk.
How is a lump sum different from settlement by bill of quantities?
With a lump sum the price is set up front and the contractor carries the cost risk. With settlement by measured quantities you pay by actual measurements and prices — it sounds flexible, except the risk and the burden of checking move to you. On a private residence I choose the first model, and this text explains why.
This content is educational and describes how I work — it is not legal advice. Discuss the structure of your own contract with your lawyer.
If you want to see what a fixed price for your project would look like — we start with a feasibility study, and you are welcome to bring your lawyer or advisor to that conversation. Let’s talk about your project.