Is a shared wall between two properties subject to division?
General Chapter
Al-Mughni
Book of Settlement
Primary text
If there is a shared wall and the owners agree to divide it lengthwise, this is permissible, and their respective shares are designated by a mark. If they agree to divide it crosswise, some companions hold it is permissible because the right belongs to both and does not leave their ownership, similar to a courtyard. If the division is lengthwise, the ruling is that the co-owner is compelled to agree to the division, similar to the division of the house, by marking the line between their shares without cutting the wall. This marking does not necessitate that one owner benefits from the other's share, evidenced by connected walls in two adjacent houses.
Supporting text
A dissenting view suggests division is impermissible because it requires distinguishing one owner's share from the other's in a way that allows exclusive use, which is impossible for a wall. Any action on one side, such as resting a beam or making an opening, affects the entire wall, thus harming the other share. Furthermore, compelling division is rejected because it involves destroying a portion of the wall, similar to cutting a shared piece of cloth.