Do we have the right to modify a common wall ?
It is possible to raise a wall, subject to bear the cost.
Everyone has the right to raise, on his own initiative, a common wall with the neighbor, although he does not fully own, said the Court of Cassation. The Court briefly recalled this principle of the Civil Code: « any proprietor can have the adjoining wall raised ».
Whoever takes this initiative is only obliged to bear the cost, adds the code, and he must also assume alone the repairs and maintenance of the part he would have built alone. Because the part raised by one of the two neighbors belongs only to him alone and is not dividing …
There is no encroachment on others when an owner decides to raise, even across its width, a wall which is half on its land and half on the neighboring land.
The joint ownership is a « forced in-division », according to the site of the notaries of France. In principle, each has rights only on its half wall, but by exception, the civil code allows both neighbors to use the entire width of the wall, if necessary, by inserting beams, for example, provided that it does not harm the other.
In this case, one of the two neighbors had not only raised the wall to its full width, but had used it as the exterior wall of a new building, piercing through it for days. All this achievement was found to be in accordance with the law by the Court of Cassation.
(Cass. Civ 3, 6.9.2018, W 17-19.430).