He was asked:
A jointly owned orchard was divided between two partners. One wished to build a wall between his property and his partner’s, but the partner refused to let him build on his land. Who must bear the cost of construction?
He answered:
The partner who refuses must be compelled to build the wall on both partners’ portions of land, if both need a screen between them.
He was also asked:
If, in the same situation, one partner refused to join the other in building, and the other built the wall at his own expense, placing part of its foundation on each partner’s share, may he prevent the partner who did not contribute from using the wall—for example, placing something on it or building upon it?
He answered:
Even if the wall belonged exclusively to one of them, he would not be entitled to prevent his neighbour from making use of it in a way that the neighbour needs and that does not harm the wall’s owner. Allah knows best.