A new provision of Poland’s developer law—Article 5a—which was intended to definitively resolve the long-standing dispute over how to calculate the usable floor area of residential units has, in practice, created the opposite effect. Instead of providing clarity, it has led to the emergence of two competing interpretations of the regulations. According to legal experts, the law, which entered into force on 13 February this year, should be urgently amended and the controversial Article 5a should be clarified as soon as possible.
The literal wording of the law refers exclusively to the PN-ISO 9836 standard, specifically the version in force on the date the building permit application is submitted. Such an interpretation could lead to including elements such as balconies, loggias, terraces or internal staircases in the usable floor area of an apartment. This could formally increase the recorded size of residential units and consequently affect their price, the share in common property and the data disclosed in land and mortgage registers.
However, just a few days after the provisions came into force, Poland’s Office of Competition and Consumer Protection (UOKiK)—in a position agreed with the Ministry of Development and Technology—presented a different interpretation. According to the authority, Article 5a should be read together with technical and construction regulations, meaning that elements such as balconies or stairs should not be included in the usable floor area.
Although this interpretation is consistent with the market’s existing practices and is aimed at protecting consumers, it has one fundamental drawback: it is not a source of universally binding law and therefore does not bind the courts.
“As a result, two parallel standards for calculating floor space have emerged—one statutory and the other what might be called systemic,” said Maciej Boryczko, Partner and legal counsel at the law firm GESSEL. “From the perspective of legal certainty in the real estate market, such a situation is unsustainable. Differences in measurement methods may lead to civil disputes, inconsistent court rulings and destabilisation of the principles used to determine housing prices. On a market-wide scale, this means increased legal risk both for developers and buyers.”
Experience from previous proceedings conducted by UOKiK shows how crucial it is to provide full and clear information about the actual size of a property already at the pre-contract stage. However, even the most reasonable interpretation by a regulatory authority cannot replace a clear and precise statutory provision.
“Decisions issued by UOKiK in 2024 and 2025 focused on the reliable and fair presentation of apartment floor areas offered by developers,” explained Karolina Olszewska, Senior Associate at GESSEL. “The authority raised concerns about the method used to determine the usable floor area of residential units and about insufficient disclosure to consumers regarding the space beneath non-load-bearing partition walls, which had been included in the apartment’s total floor area.”
One example is decision RLU-1/2025, in which UOKiK challenged a situation where a developer did not include the space beneath non-load-bearing partition walls in the usable floor area of an apartment. The issue became apparent when the ownership transfer agreement was signed. At that stage, the actual area of the apartment turned out to be larger, meaning that consumers were required to pay an additional amount for the floor area beneath removable partition walls.
“The only realistic solution to the current impasse is an urgent amendment to Article 5a that clearly defines the relationship between the PN-ISO standard and technical construction regulations and explicitly specifies which elements of an apartment should be included in the usable floor area,” Boryczko concluded. “Without such clarification, the housing market will remain in a state of permanent interpretative uncertainty, and the financial and legal costs of this ambiguity will ultimately be borne by all participants in the market.”
Legal experts also emphasize that Article 87 of the Polish Constitution clearly defines the closed catalogue of sources of universally binding law. These include the Constitution, statutes, ratified international agreements and regulations. Positions issued by administrative authorities—even if agreed with a ministry—do not fall within this catalogue.
