I own two condo units that are connected by a doorway in the common brick wall. Now I'd like to rent one of the units and close the doorway. I was wondering if it was possible to leave both options open, that is if there is a way to close the opening but to keep feasible to reintroduce it at wish.
What would be some ways to do that? I was thinking of building a wall inside the opening and keep the doorframe, but what would be possible materials?