Can you build against or raise a party wall?
Yes. Each co-owner may build against the party wall and embed beams in it (Article 657), and may raise it at their sole expense (Article 658). A neighbour can also acquire party-wall status over a private wall by reimbursing half of what it cost and half the value of the land beneath it (Article 661).
The right to rest a structure against the wall (Article 657)
Article 657 of the French Civil Code allows each co-owner to build against the party wall and to place beams or joists within almost the full thickness of the wall, to within fifty-four millimetres. The neighbour keeps the right to have those beams cut back to half the wall if they themselves wish to rest a structure or a chimney against it at the same spot.
Article 662 lays down a neighbouring rule: no recess, and no structure applied to or resting within the body of the party wall, without the other owner's consent or, if consent is refused, without having experts settle the means needed to ensure the new work does not harm their rights. How the right of support of Article 657 fits with the consent requirement of Article 662 is assessed case by case by the courts: in practice, the neighbour's written agreement secures the operation.
Raising the wall at your own expense (Article 658)
A co-owner may have the party wall raised without the other's agreement, but bears the expense alone. Article 658 places on them the cost of the raising, the upkeep of the part added above the common height, and an indemnity for the additional load imposed on the wall.
If the existing wall cannot bear the raising, the person raising it must have it rebuilt entirely at their own expense, the extra thickness being taken on their own side (Article 659). The raised part belongs to them alone until the neighbour has acquired party-wall status over it.
Acquiring party-wall status over a neighbouring wall (Article 661)
An owner whose plot adjoins a private wall may acquire party-wall status over it, in whole or in part, without the wall owner's agreement. Article 661 makes this acquisition conditional on reimbursing half of the expense the wall cost, or half for the portion made a party wall, and half the value of the land on which it stands.
The same mechanism applies to the raised part: a neighbour who did not contribute to the raising may acquire party-wall status over it by paying half of the expense it cost, assessed as at the date of acquisition and taking account of the condition of the raised part, plus the value of half of the land supplied for the extra thickness, if any (Article 660). This right of compulsory acquisition makes it easier to rest a new construction against the wall.
Frequently asked questions
Do you need the neighbour's agreement to raise a party wall?
No. Article 658 allows a party wall to be raised without the neighbour's agreement, but at the sole expense of the person raising it, including the upkeep of the added part and an indemnity for the additional load borne by the wall.
How much does acquiring party-wall status over a wall cost?
Article 661 sets the price at half of the expense the wall cost, or half for the portion made a party wall, and half the value of the land on which it stands. That expense is assessed as at the date of acquisition, taking account of the condition the wall is in.
Can you attach a shed or a conservatory to a party wall?
Yes, under the right of support in Article 657, provided it does not harm the wall's strength or the neighbour's rights. Fixings embedded in the body of the wall come under Article 662 and require the neighbour's agreement or a settlement by an expert.
Read next
- Code civil, article 657 (Légifrance)
- Code civil, article 658 (Légifrance)
- Code civil, article 661 (Légifrance)
- Code civil, article 662 (Légifrance)
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