Where the deeds are silent or contradict one another, the law presumes terraces, balconies, balustrades and railings to be common. It does, however, exclude from that presumption the surface finish of a terrace or balcony where it cannot be seen from outside. And where a co-owner alone enjoys a common part, day-to-day upkeep may fall to them, but not the cost of the structural shell, and in particular not waterproofing. (loi du 16 mai 1975, art. 3.2 et 7)
Why is a balcony not legally a single thing?
Because it brings several layers together.
There is the slab, the waterproofing, the visible finish, the railing, the drainage and sometimes elements tied to the facade.
The law lays down a presumption, but it only applies where the deeds are silent or contradictory. The rules and the deeds of the building therefore remain the first document to consult.
Is the tiling private?
The law excludes from the presumption of common part the surface finish of terraces and balconies that cannot be seen from outside. (loi du 16 mai 1975, art. 3.2)
That does not mean an owner may remove everything lying beneath the tiles.
An apparently decorative job can reach the waterproofing or change the drainage fall, and therefore affect a part whose cost is no longer borne by the same person.
Who maintains a terrace held for exclusive use?
Where the rules reserve the use of a common part to one co-owner, the upkeep of that part falls to them in principle.
But the law immediately adds an exception: that rule does not apply to the cost of the structural shell, and in particular waterproofing. (loi du 16 mai 1975, art. 7)
This distinction explains why "I am the only one who uses it" does not automatically mean "I pay for everything".
What happens when a defect causes water ingress?
The priority is to stop the damage getting worse.
Next, the element concerned has to be identified: surface finish, waterproofing, drainage, slab or facade.
The law provides that the association is liable for damage caused by a construction defect or a failure to maintain the common parts. (loi du 16 mai 1975, art. 11)
This does not settle every possible liability, but it explains why water ingress affecting a common element has to be taken seriously and quickly.
May I change the railing or enclose the terrace?
A railing is presumed common where the deeds say nothing else. Changing its appearance or enclosing a terrace may also affect the external appearance.
The project may then fall under the authorisation regime for private works affecting the common parts or the exterior. (loi du 16 mai 1975, art. 16 b))
Why keep the paperwork from the works?
Because waterproofing is only visible for a few hours before it is covered over.
Photographs, specifications, invoices and the decision of the meeting are what make it possible to know what was done when the problem comes back several years later.