Do I need a building permit to replace windows in 2026? What Law 50/1991 says

One of the most frequent questions before replacing windows is whether you need a building permit. The good news: in most cases, replacing existing windows does NOT require a permit. There are, however, concrete situations in which the permit becomes mandatory, and working without one can attract fines between 1,000 and 100,000 lei. This guide explains, based on Romania's Law 50/1991, when you can replace windows freely and when you need approval.

The general rule: identical replacement requires no permit

According to Article 11 of Law 50/1991, repairs and replacements of interior and exterior joinery can be done without a building permit, provided the shape and dimensions of the openings and joinery are preserved. This remains valid even if the material changes — for example, replacing old wooden windows with PVC or aluminium windows — as long as the wall opening and dimensions stay the same.

In practice, if you remove an old window and install a new one of the same dimensions, in the same opening, without modifying the masonry, you are fine and do not need to ask the city hall for anything.

> Important exception: the rule does not apply to buildings declared historical monuments or located in protected areas. There, any intervention requires a permit and special approvals.

When you DO need a building permit

The permit becomes mandatory when the work goes beyond a simple identical replacement. The main situations:

The reason is that these works affect either the load-bearing structure or the architectural appearance of the building — two aspects the law expressly protects.

What "modifying the façade" means

Many people do not realise that changing the colour of the joinery or the way the windows are divided can constitute a façade modification. If your block has white windows and you install anthracite windows, or if you replace a two-sash window with a three-sash one, you change the façade appearance. In a block, this also relates to the owners' association regulations, which may require a unified appearance to be maintained.

To avoid problems, before choosing the colour or configuration, check the association regulations and, if in doubt, request an urbanism certificate from the city hall — it tells you exactly what is allowed.

The procedure, if a permit is required

When a permit is mandatory, the general steps are: obtaining the urbanism certificate from the city hall (within 30 days), preparing the technical documentation (DTAC) by a designer, obtaining the approvals required by the urbanism certificate and submitting the file. According to Emergency Ordinance 31/2025, authorities are obliged to respond within 15 days for building permits, with exceptions for special approvals (environment, historical monuments).

The risks of working without a permit

If you carry out works for which a permit was mandatory, Law 50/1991 provides fines between 1,000 and 100,000 lei. In addition, authorities can order the works to stop and require legalisation. In the case of historical monument buildings, unauthorised interventions can even be considered offences. When the home is later sold, the lack of documents can block the transaction at the notary.

> Any person — not just neighbours — can notify the city hall or the State Construction Inspectorate about unauthorised works.

FAQ — Window replacement permit

Do I need a permit to replace the windows in my apartment?

Generally no, if you preserve the shape and dimensions of the openings and joinery. According to Law 50/1991, identical window replacement is permitted without a permit, even if you change the material. Exceptions are historical monument buildings and those in protected areas.

When does a building permit become mandatory for windows?

When you modify the opening size, the window shape, the façade appearance (colour, division), when you enclose a balcony or add a terrace, or if the home is a historical monument or in a protected area.

Does changing the window colour affect the façade?

Yes, changing the colour of the joinery or the configuration of the windows can be considered a modification of the façade appearance, which requires a permit. In a block, it also relates to the owners' association regulations on unified appearance.

What fine do I risk if I replace windows without a permit when one was required?

Law 50/1991 provides fines between 1,000 and 100,000 lei for works carried out without a permit, when one was mandatory, plus stopping the works and the obligation to legalise.

Must I notify the owners' association?

For identical replacement it is not a legal obligation, but it is recommended. For works that affect the façade or common areas, the association's approval may be required according to its regulations.

Neofort BIZ installs Salamander PVC and Alumil aluminium joinery in Bucharest and Ilfov, respecting existing opening dimensions where a permit is not desired. Request a free on-site assessment.