If a planning violation surfaces during the sale, disclose it, then either apply for a regularisation permit or agree with the buyer that they take it on with the price adjusted. The notary records the infraction in the deed under the CoDT (2026).
Discovering an unpermitted extension or a converted garage mid-sale is stressful, but it is a manageable situation with three realistic routes, not a dead end.
The first step is always disclosure. Under the CoDT the notary must mention a known infraction in the deed, so hiding it is neither lawful nor safe (CoDT, 2026). Once it is on the table, the main option is regularisation: you file a retrospective permit application with the commune, using the same forms as a normal permit (Annexe 4 with an architect, Annexe 6 without), and the works must comply with current zoning and municipal rules to be accepted (fautilunpermis.be, 2026). Instruction follows the standard 30 to 115-day timeline, and there is no guarantee of approval if the works breach current requirements.
Costs vary widely. A regularisation dossier commonly runs from 3,000 to 15,000 euros all in, and the delegated official may propose a transactional fine, which can range from a few hundred euros to 25,000 euros or more depending on the case (fautilunpermis.be, 2026).
The counter-intuitive practical answer: you do not always have to regularise before selling. Many transactions proceed by transferring the property as-is, with the buyer accepting the infraction and the price reduced to reflect the regularisation cost and risk. What matters is that the choice is informed and written into the compromis. Easyhome helps you compare regularising, negotiating or restoring, and coordinates with the architect and notary.
At a glance
- Disclose the infraction, the notary records it in the deed (CoDT, 2026)
- Option 1: apply for a regularisation permit at the commune
- Use Annexe 4 (with architect) or Annexe 6 (without), same as a normal permit
- Works must meet current zoning and municipal rules to be regularised
- Instruction follows the 30 to 115-day timeline (fautilunpermis.be, 2026)
- Regularisation dossier commonly 3,000 to 15,000 euros all in
- A transactional fine may apply, from hundreds up to 25,000 euros or more
- Option 2: sell as-is with the buyer accepting it and the price adjusted