Updated: September 2026 · Legal status: August 2026
It depends on the height of the structure and whether the installation interferes with the building’s structure. The old ruling we cited here (Provincial Administrative Court in Gdańsk, II SA/Gd 329/14), was based on a version of the regulations that is no longer in effect following the 2020 amendment—which is why we are describing the current situation.
Thresholds for structures on an existing building
The law treats the installation of a mast on a roof as the installation of a technical device on an existing structure, rather than as construction. The structure up to 3 m — Neither a permit nor a notification is required (Article 29(4)(3)(a) of the Building Code). Over 3 m and up to 12 m — notification, 21 days for the authority to object, followed by tacit approval (Article 29(3)(3)(a)). Over 12 m — building permit.
These 3 and 12 meters are measured from the point where the structure is attached—that is, from the roof surface—and not from ground level. The law does not explicitly define this—this method of measurement stems from a January 2026 ruling by the Supreme Administrative Court (NSA) and a June 2026 position statement by the National Building Control Authority (GUNB). Therefore, in the application, we always provide both dimensions: the structure’s own height and its elevation above ground level.
When the county administration is right to require a permit
First, when the structure has a roof span of more than 12 meters. Second, when installation requires interference with the building’s load-bearing structure—such as cutting through the ceiling, installing new joists, reinforcing the roof trusses, or drilling into a load-bearing wall—and the building is not a single-family residence. Such work is not covered by the exemptions. Simply bolting the structure to existing elements, without altering their function, is considered installation. This is determined by a structural assessment of the roof—the law does not require it, but we always recommend it.
Third, the authority may require a building permit even if the notification was filed correctly (Article 30, paragraph 7), if it determines that the project could endanger the safety of people or property, deteriorate the environment or health and sanitation conditions, or increase nuisances to neighboring areas. The guidelines are vague, so do not schedule installation until 21 days have passed since the notification.
Also, be aware that structures with their own poured foundation or a load-bearing frame independent of the building may be considered a separate structure by the authorities, in which case the exemption does not apply. The authority may classify raising an existing mast as an extension of a structure; this is a contentious issue, so check with the authority before starting work.
A complete description—ground-mounted, rooftop, aviation, historic sites, and Natura 2000—can be found in the post about the building permit for the mast.
The classification of a specific investment is determined by the competent authority on a case-by-case basis. This text describes the legal situation (as of August 2026, Construction Law, consolidated text: Journal of Laws 2026, item 524) and our experience—it does not constitute legal advice.