Remember!

Here is the translation of the Polish text you provided: If the attic was designated in the house project as usable, but we want to change its functionality,
we do not have to apply for a change of use.
However, the planned construction work still requires a permit or notification.
Works that do not require any formalities include, for example:
– connecting the attic to the attic or replacing existing water and sewage installations,
heating and electrical systems and installation of sanitary equipment, radiators, etc.;
– construction of partition walls;
– replacement of windows and doors without changing the size of openings;
– replacement of internal stairs;
– finishing the attic walls and laying floors on it;
– insulation of the roof and walls (if the building is not higher than 12 m);
– replacing the roof covering, but be careful! – only in a detached building and sufficiently distant from the plot boundaries (i.e. one whose area of influence does not extend beyond the plot).
A change in the use of the attic may be made within 2 years of its notification to the office (Article 71(4)).

Regarding attic adaptation, the new construction law (text of the act after the amendment – Journal of Laws of 2020, item 1333) provides for two options: reporting construction works to the office or obtaining a building permit.