Formalities and financing
How to check which Polish building regulations apply to a project
In brief
In 2026, building changes include, among others, selected formalities and procedures concerning improperly executed works. Individual provisions may have different entry-into-force dates. For a roof project, transitional rules on technical conditions must also be taken into account. It is not enough to read a headline about simplifications. Below we indicate what to check as at 1 November 2026. An amendment may be adopted in one year, announced later and enter into force on several dates. In online text it is easy to confuse these stages. A draft bill is not yet binding law. A ministry announcement also does not replace a published act.
Why does the article date alone not confirm the law?
An amendment may be passed in one year, announced later and come into force on several dates. In online text these stages are easily confused. A draft bill is not yet a binding provision. A ministry announcement does not replace a published act either. When planning works, you must check the specific legal basis and its date of application.
Most changes under the Act of 4 December 2025 came into force on 7 January 2026. The Act also provided for exceptions to that date. The statement ‘new law from 2026’ is therefore too general for a construction decision. The check should cover the provision being amended, the transitional rule and any rules for proceedings already commenced.
Do the simplifications cover every construction project?
No. Exemptions from a permit or notification relate to specified structures and works. The conditions set out in the Act must still be met. The choice of trapezoidal steel sheet, steel structure or sandwich panel does not in itself exempt you from formalities. Qualification depends on the characteristics of the project, not on the slogan used in a contractor’s offer.
For a roof, maintenance, renovation, reconstruction and possible raising must be distinguished. Replacing material may fall within restoration to the original condition, but changing the building height is not a simple replacement of covering. If the scope changes during preparation of the investment, check the procedure again. Formalities established for narrower works may no longer suffice.
What do the new rules mean for older works?
The provisions provide various paths for works carried out in breach of requirements. They do not, however, introduce a rule that every unauthorised development becomes lawful after ten years. Simplified legalisation of a building without the required basis is still linked, as a rule, to the expiry of at least twenty years from completion of construction and to further conditions being met.
A separate regulation applies to specified works completed at least ten years earlier, including significant departures from a decision or design. The procedure depends on the type of irregularity. Documents and a safety assessment may be required. The age of the roof alone, or the fact that there were no inspections for years, does not confirm that the structure complies with the law.
Can you make a mistake first and then correct it?
The new provisions allow the supervisory authority to instruct the investor to remove significant departures. The authority then checks that the execution has been adjusted, as a rule after a specified period or earlier on application. This is not a general permission to start works outside the design. The application of this possibility depends on the statutory conditions.
On site, it is more sensible to agree a change before carrying it out. This also applies to roof windows, roof slope geometry or loft conversion. The availability of a different material should not lead to independently changing the structural parameters. The designer assesses the significance of the modification and the documentation required. Remedial work after the event may require dismantling completed layers.
How do you check thermal requirements after the changes?
From September 2026, transitional provisions on the application of the existing technical conditions gained particular importance. The Act provides mechanisms for their continued application for eighteen months from 20 September 2026. The details depend on the investment procedure. In specified cases, a declaration by the investor adopting the earlier provisions is required.
This does not mean that requirements for roof insulation disappear or that a new PIR thickness is automatically introduced. The heat transfer coefficient applies to the entire building element, not just the insulation board. Selection takes into account the material properties, the other layers and thermal bridges. The draft of the new regulations should be kept separate from the provisions that can actually be applied to specific documentation.
How do you avoid a decision based on outdated information?
Check the text of the Act, its amendments and the official description of the procedure. Record the verification date and the basis adopted in the design. Where the scope of works is unclear, present a full description to the designer and the competent authority. A question about ‘roof replacement’ alone may give too general an answer if you are in fact also planning to raise the walls or change the structure.
Nor should you assume that from 2026 every construction project must use only an electronic site log. The provisions temporarily retain the possibility of issuing paper logs until the end of 2031, subject to statutory reservations. For the investor, the most important thing is that the documentation complies with the correct procedure. The organisationally convenient form should be chosen according to the requirements in force, not according to a date heard somewhere.
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