The developer wants an extra payment: can the agreed apartment price change?

You agreed a purchase price, but a letter now says material costs have increased and you must pay more. The immediate task is not to choose between paying at once and abandoning the apartment. Request the contractual and legal basis for the demand, together with its calculation.

Article 20a of the Obligations and Contracts Act establishes the binding force of agreements. The seller's notice alone does not replace the agreed price without an applicable contractual or legal basis.

Identify the pricing arrangement

Distinguish a fixed total price, a price per square metre subject to final measurement, and an indexed price. Check the treatment of taxes, finishing works, parking and other promised elements.

An additional charge for a specifically ordered change to the project is different from a general increase demanded from all buyers. Compare the request with the agreement, specifications and any subsequent changes you approved.

Examine the indexation mechanism

If the contract contains an adjustment clause, identify its trigger, index or other measure, period and calculation base. Request a calculation that can be reproduced. Referring to inflation does not, by itself, explain why the particular amount is due.

A signature does not end the assessment of the clause. Where the relationship is between a trader and a consumer, unfair-terms rules may apply. Not every indexation provision is prohibited, and not every unilateral increase is permissible. Wording, transparency, applicable exceptions and circumstances matter.

Hardship does not itself create a new invoice

Article 307 of the Commerce Act allows a court to amend or terminate a contract under specified conditions involving unforeseen circumstances and conflict with fairness and good faith. Whether that provision applies to the particular relationship requires separate assessment.

A letter invoking it is not a court decision changing the price. Nor does every cost increase necessarily satisfy its conditions.

Before accepting revised terms

Read the entire amendment. Alongside a higher price, it may introduce a later completion date, a changed property description, revised floor area or a release of accrued claims. If accepting a compromise, clearly record what you receive in return and which existing terms remain.

Do not automatically stop all payments. Distinguish the disputed extra amount from instalments already due, so that the response does not create separate non-performance on your side.

For review, assemble the agreement, price and area schedules, payment records, increase notice and proposed amendment. A written response based on these documents is more useful than an argument by telephone.