Is it permissible for a neighbor to build upon, place a barrier upon, or place lumber upon the wall of another with permission?

Primary text

It is permissible for the owner of a wall to grant his neighbor permission to build upon it, place a barrier upon it, or place lumber upon it in a location where the neighbor does not inherently have the right to do so. Once the action permitted is executed, the loan (A'riyah) becomes binding, and the lender cannot revoke it. The borrower is not obligated to remove what was done because the lender's permission implies permanence and continuation, and removal would cause harm to the borrower. This is analogous to lending land for burial or planting; the lender cannot demand the removal of the deceased or the plants without compensation.