A co-owner may fit out their private parts, but they cannot treat a facade, a floor slab, a duct or a common installation as if it belonged to them alone. Where the works affect the common parts or the external appearance, the authorisation falls to a majority of the votes of all co-owners. If that majority is not reached, a second meeting may decide by a majority of those present or represented. (loi du 16 mai 1975, art. 16 b), dernier alinéa et art. 15)
Which works really stay private?
Repainting a room or replacing an interior finish without touching a common part does not have the same reach as drilling through the structural shell, altering a facade or working on a common pipe.
The first step is therefore to establish what the element concerned actually is.
Which rule applies if my works affect the common parts?
Article 16 b) of the law provides for the authorisation given to certain co-owners to carry out, at their own expense, works affecting the common parts or the external appearance, provided they remain consistent with the purpose of the building.
The decision is taken by a majority of the votes of all co-owners. (loi du 16 mai 1975, art. 16 b)).
The law also provides that, where consent is refused, the court may authorise the works if they harm neither the soundness nor the appearance of the building and do not inconvenience the other co-owners. (loi du 16 mai 1975, art. 16 b))
What has to be put forward before the vote?
The implementing regulation requires a draft resolution to be notified where the meeting is to decide on an authorisation of this kind. That draft must be sent at the latest together with the agenda. (RGD du 13 juin 1975, art. 5, 5°, tel que modifié par le RGD du 28 novembre 2024)
Describing the project is therefore not merely good practice: an important decision has to be prepared with an identifiable resolution.
And if the first majority is not reached?
For decisions falling under article 16, the law provides for a second meeting deciding under the majority of article 15, that is, the majority of the co-owners present or represented. (loi du 16 mai 1975, art. 16, dernier alinéa)
Where that second meeting deals only with matters already put to the first, the notice period may be reduced to eight days. (RGD du 13 juin 1975, art. 11)
Is this the same as improvement works decided by the co-ownership?
No.
Article 16 b) covers a co-owner who wishes to carry out, at their own expense, works affecting the common parts or the exterior.
Improvement works decided collectively by the association fall under a different regime, in particular articles 26 and 27 of the law, combined with the double majority laid down in article 17.
Mixing the two regimes easily leads to applying the wrong majority.
Can the co-ownership impose any transformation it likes on my flat?
No.
Whatever the majority, the meeting cannot impose on a co-owner a change to the purpose of their private parts, or to the way those parts may be enjoyed, as these result from the rules. (loi du 16 mai 1975, art. 18)
Conversely, a co-owner cannot obstruct collective works properly decided upon where the law requires them to be carried out even inside private parts. (loi du 16 mai 1975, art. 28)
And if collective works cause a loss?
The law provides for compensation where a co-owner suffers a loss as a result of collective works, in particular a permanent reduction in the value of their unit, a serious interference with enjoyment, or damage. (loi du 16 mai 1975, art. 31)