Changes in Polish building law to check before starting a project

A significant part of the changes introduced by the Act of 4 December 2025 has been in force since 7 January 2026. Individual regulations, however, had different deadlines. Further amendments to the Act appeared in subsequent months. When analysing, therefore, the current wording of the provision must be used, not merely a communiqué published before the amendment came into force.

This matters especially when proceedings began earlier. Transitional provisions may determine how such a case is conducted. An application submitted before the change and a new project are not always assessed identically. Before ordering material, establish on what documentation and legal basis a specific investment will be carried out.

The amendments modify the catalogues of structures and works covered by a permit, notification or exemption. This does not, however, mean general freedom to build. Every exemption has a defined scope. The parameters of the structure, its purpose, location and additional conditions must be checked together. A shorthand slogan about less bureaucracy does not replace such an assessment.

For an investor ordering a roof, it is important to distinguish between renovation, reconstruction and raising. A mere change of material may have different consequences than raising the roof slope or building a new dormer. The lightness of the sheet metal or the prefabrication of the cladding does not constitute a separate exemption from formalities. The scope of works should be described before choosing the procedure.

The provisions provide for the possibility of the building supervision authority issuing an instruction in specified cases of significant deviation during the carrying out of works. The authority may indicate the need to bring the works into compliance. The instruction is documented in the inspection report and the construction log. This is a power of the authority, not a guaranteed stage of every case.

The instruction is followed by verification of compliance with the obligation, as a rule after 60 days or earlier at the investor’s request. Failure to bring the works into compliance triggers further actions provided for by the Act. This regulation should not be treated as consent to deliberately changing the design. The simplest approach is to agree the change before carrying out the works.

No. A distinction must be made between construction without the required consent and specified deviations from the approved documentation. In the first group, the simplified legalisation under Article 49f is still, as a rule, linked to the expiry of at least 20 years from completion of construction. The ten-year period in the new provisions concerns other, expressly indicated situations.

For works that significantly deviate from the permit or design, the Act provides for the appropriate application of the simplified procedure once the conditions are met. For some other infringements, it requires an assessment of the risk to life or health. Classification is therefore crucial. The age of the building alone does not yet indicate which procedure will be applied or which documents will be required.

The deadline for issuing a paper construction log has in principle been extended to the end of 2031. This should not be confused with an obligation to immediately replace every construction log already being kept. The method of documenting works must be determined in accordance with the procedure and the construction situation. Electronic documentation remains a separate available route.

The transitional provisions also provide for the possibility of applying certain existing technical conditions for 18 months from 20 September 2026, subject to a required declaration by the investor. The choice of design basis should be consistent. Favourable fragments of different versions of the provisions should not be combined arbitrarily, nor should a draft regulation be treated as law in force.

Ask the designer to confirm the current requirements for the specific investment. Determine whether a change of covering, insulation or geometry requires an adjustment to the documentation. In the case of sandwich panels, the thermal and fire requirements of the entire system must also be checked. A product’s declaration of parameters alone does not confirm the compliance of the entire building.

Record the date of verification and keep the essential documents. Before starting the next stage, check whether the scope of the undertaking has changed. The provisions are of practical significance when they translate into a proper design and the correct course of works. This allows administrative changes to help organise the investment rather than lead to costly corrections.