Fixed-Price Building Contracts in Poland: Extra Works Disputes

You agreed a fixed price for a renovation or building job, and halfway through, the builder produces a list of "extra works" and asks for more money, arguing that "with a fixed price, something always comes up." Whether that extra payment is actually owed depends on what those additional works really are — a genuine change to the scope of the contract, or something the builder should have priced in when quoting the fixed sum in the first place. This guide sets out where that line falls, and how to settle changes safely before a dispute ends up in court.

This guide is general legal information, not legal advice. How the rules apply depends on the wording of the contract, the supporting documentation and the circumstances of the case — including whether it is a consumer, civil or commercial matter, and whether the contract should be treated as a umowa o dzieło (contract for a specific work) or a umowa o roboty budowlane (construction works contract). We do not guarantee any outcome or settlement figure. Where advice or representation is needed, the matter should be assessed by a qualified Polish lawyer. Twoja Sprawa helps you organise the documents for that assessment.

Key points

• A fixed price (ryczałt) is a single, pre-agreed sum for the whole agreed scope of works — as a rule, it shifts the risk of a miscalculation onto the builder.
• "Extra works" means work outside the originally agreed scope — not simply a more expensive way of doing what was already ordered. This distinction determines whether a demand for extra payment is justified.
• The exception to a fixed price being binding is narrow — a court may only consider adjusting the fee where there has been an extraordinary, unforeseeable change of circumstances that threatens the contractor with a serious loss.
• A plain rise in material costs, or an error in the builder's own costing, is generally not covered by that exception and does not on its own justify a unilateral price increase.
• Any change to scope or price is best confirmed in a written amendment — a verbal "while we're at it, let's also do this" is a straightforward route into a dispute.
• How the contract is classified (umowa o dzieło vs umowa o roboty budowlane) affects, among other things, the limitation period for claims — this needs a lawyer's assessment.

Fixed price vs cost estimate — the two main contract models

Before assessing a demand for extra payment, establish how you actually agreed the price in the first place. In practice, renovation and building contracts tend to follow one of two models:

• Fixed-price contract (wynagrodzenie ryczałtowe) — a single, set sum for the whole agreed scope of works (e.g. "bathroom renovation for PLN 30,000"). The builder takes on the risk of their own costing — if they under-priced labour or materials, they generally cannot demand a higher fee for that reason alone.
• Cost-estimate contract (wynagrodzenie kosztorysowe) — payment based on a breakdown of planned works, quantities and unit prices. Here, a change in scope or quantity of works may justify an adjustment to the fee, but the exact rules for that adjustment need to be checked against the specific contract.

Which model applies follows from the wording of the contract — or, in the absence of that, from how the price was actually set in practice. A single lump-sum figure with no itemised breakdown is usually a sign of a fixed-price arrangement, but the final classification of a specific document is a legal assessment.

The limits of a fixed price — what the agreed sum covers

A fixed price covers the entire scope of works agreed in the contract, including anything that is a natural, foreseeable consequence of that scope. What's often disputed is whether a given piece of work fell within the original scope or went beyond it. When assessing this, it helps to look at:

• the description of the scope of works in the contract and the quotation/cost estimate on which the fixed price was based,
• whether the additional work arose from a decision by the client (e.g. changing the tile layout) or from circumstances beyond anyone's control (e.g. discovering a hidden fault in the plumbing or wiring),
• the fact that a rise in the cost of materials or labour on the builder's side is, as a general rule, the builder's own risk and is not, by itself, grounds for a price increase.

Extra works — when the builder can demand extra payment

In everyday usage, "extra works" means work that the parties did not provide for in the contract or in the cost estimate underlying it. Typical disputed examples include discovering a hidden defect during a renovation (e.g. rotten wiring or pipework), a change of mind by the client during the works (a different layout, more expensive materials), or work required by regulations or site conditions that could not have been foreseen at the quoting stage.

For a demand for extra payment to have a reasonable chance of being justified, it should generally meet several conditions: the work genuinely went beyond the original scope, the client knew about it and agreed to it (ideally in writing), and its price is properly documented. If the builder did something "on the side" without agreeing it first, and only presents a bill at the end, that does not automatically create an obligation to pay the amount demanded.

Extraordinary change of circumstances — can a court raise the fixed price

The Polish Civil Code provides a narrow exception to the rule that a fixed price is binding. If, as a result of a change of circumstances that could not have been foreseen when the contract was signed, completing the work for the agreed sum would expose the contractor to a serious loss, the contractor may ask the court to increase the fixed price, or to terminate the contract.

It's worth remembering: it is the court, not either party to the contract, that decides whether an "extraordinary change of circumstances" has occurred — a one-sided demand for extra payment on site is not the same thing as a court ruling. Ordinary, foreseeable fluctuations in the cost of materials or labour are, as a rule, not treated as such a circumstance, though the assessment always depends on the specific facts. A builder simply saying "prices have gone up, I need to charge more" is therefore not, on its own, sufficient grounds to demand extra payment outside of court — this is an exceptional claim that needs a lawyer's assessment.

Contract amendments — how to settle scope changes safely

The best way to avoid a dispute is to confirm every change of scope in writing before the additional work is carried out: a short amendment to the contract (aneks) describing the new scope, the price and any change to the deadline, or — where there's no time for that — at least a confirmation by email or text message. Agreeing the price of extra work before it starts, rather than after, protects you from an unpleasant surprise in the form of a finished bill.

If the builder refuses to sign an amendment and simply demands extra payment "on trust", it's worth putting your position in writing — for example, stating that you dispute the demand, or that you are paying the disputed amount under reservation of a right to reclaim it.

Documents and evidence in a fixed-price dispute

Frequently asked questions

Can a builder on a fixed-price contract ever demand extra payment?

Yes, but only in narrow situations: where the work genuinely goes beyond the agreed scope, or where there is an extraordinary, unforeseeable change of circumstances assessed by a court. A costing error by the builder, or an ordinary rise in prices, is generally not enough on its own.

What if I signed off on completion, and only afterwards received a bill for extra payment?

It depends on the wording of the completion/handover statement and any earlier agreements — if you did not previously agree to the extra work or its price, there is no automatic obligation to pay.

Can I withhold payment until the dispute is resolved?

It depends on the circumstances, including whether the main works were carried out in accordance with the contract. Withholding payment can be risky without first assessing the situation — it's worth getting a lawyer's view before making that decision.

As a business (B2B), do the same rules apply as for a consumer ordering a home renovation?

The rules on fixed prices and extra works derive mainly from the Polish Civil Code and apply broadly in the same way regardless of the status of the parties, but a business does not benefit from the additional protections given to consumers, and in B2B relationships the literal wording of the contract and cost estimate carries more weight.

Need help with this kind of matter?

If a builder is demanding extra payment on top of a fixed price and you're not sure whether that demand has any basis, it's worth starting by getting your documents in order: the contract, the cost estimate, correspondence about scope changes, and any invoices. Send us the documents relating to your renovation or building project — we'll help you organise them for further review by a lawyer. Submitting the form does not create a contract and does not commit you to anything.

Related guides from this section:

• Builder demanding more than the agreed price — do you have to pay? (in Polish) — a practical step-by-step scenario.
• What a good contract with a renovation crew should contain (in Polish) — how to protect yourself against a price dispute from the outset.
• Renovation without a written contract — how to pursue a claim (in Polish) — where the price arrangements were only verbal.
• All guides on disputes with businesses (in Polish) — the full topic base.