In Poland, much of the amendment adopted at the end of 2025 entered into force on 7 January 2026, but not every provision takes effect on the same date. An investor should check the scope of the planned works, the date they are undertaken and the documents for the specific project, rather than relying on the year in the Act's title alone. Selected exemptions from formalities and the procedure for departures from the design have their own scopes, and the rules allow the previous technical conditions to be applied temporarily. Design decisions are left to the designer.

In Poland, preparing a build starts with establishing which documents and approvals are needed for the specific plot and scope of work. Check the land use and development conditions, because the local plan may define roof geometry, pitch or covering appearance, and its absence does not mean full freedom. For a renovation, review existing documents, especially truss drawings, which may differ from the built work. Describe what will be created, removed and left unchanged, distinguishing covering, structure, insulation and attic use.

In Poland, the consequences of unauthorised construction depend on the type of irregularity: missing required consent, failure to notify, or a significant deviation from the approved design may lead to supervisory proceedings, an obligation to prepare documentation, a fee, or demolition. Legalisation is not automatic. Before renovating an old roof, it is worth establishing both the condition of the structure and the legal scope of earlier works, because the irregularity may concern the whole building or part of it. It is essential to determine the date of the works, the requirements in force at that time, and the actual extent of the changes.