but if the residents of the alley reach a monetary settlement with him, it is valid.
It is likewise permissible to open small windows.
A wall that stands between two proprietors may belong exclusively to one of them or be held in common. If it is exclusively owned, the other may not rest his beams on it without the owner’s permission, according to the new position, and the owner cannot be compelled to grant such permission. Should the owner consent gratuitously, that consent counts as a loan; he may revoke it before the beams are placed, and—on the sounder view—even after they have been placed. Revocation gives him the choice either to leave the beams in place for a rental fee or to have them removed while claiming arsh (compensation for the resulting loss in value). Others maintained that the sole effect of revocation is the right to demand rent.
If he allows the placement of beams and building upon them for consideration, then: if he leases the top of the wall for that purpose, the contract is a lease; but if he says, “I have sold you the top of the wall to build on,” or “I have sold you the right to build on it,” the sounder view is that the contract blends sale and lease. Once the structure is built, the wall’s owner may never demolish it. Should the wall collapse and the owner rebuild it, the purchaser is entitled to rebuild his construction.
Whether the permission was granted for payment or gratis, the dimensions of the area to be built upon—its length, breadth, wall thickness, their configuration, and the form of the roof they will carry—must all be specified. Where the permission concerns building on land, stating only the size of the building site suffices.
With respect to a shared wall, neither partner may set his beams on it without the other’s consent, according to the new opinion, nor may he drive a peg into it or open a window without permission. He may, however, lean against it himself or prop on it belongings that cause no harm, and he enjoys the same liberty with the wall of a stranger. Under the new position he may not force his partner to repair the wall. If he wishes to rebuild a fallen section with his own materials, he may do so; the rebuilt part becomes his property—he may place on it whatever he wishes and demolish it whenever he pleases. Should he say to the other, “Do not demolish it and I will pay you for my share,” the builder is not obliged to agree. If he wants to rebuild it using their shared masonry, the other may forbid him; but if they cooperate in rebuilding it with that masonry, it returns to joint ownership as before. When one of them rebuilds the wall on his own and the other stipulates an increased share for him, that is permissible, and the increase corresponds to the work he performed in the other’s portion.
It is permissible to conclude a settlement—against payment—granting someone the right to channel water through one’s property or to deposit snow there.
If two neighbors dispute the ownership of the wall that separates their properties, then if the wall adjoins one party’s building in such a way that it is known the two structures were erected together, that party is deemed to possess it; otherwise, it is held jointly. Should either of them produce evidence, judgment is rendered in his favor; if not, they both take an oath. If they both swear—or both refuse—the wall is considered common to them. And if one of them swears