I have a cellar room off the side of my basement (only lawn above it). Can I just seal it off with cinderblock? It leaks water when it rains. The room is only accessible through the basement bedroom through a tiny door (2’x3’). It is maybe three feet below the lawn and if it rains really hard for awhile, some water will leak through the ceiling in it (it seeps through the concrete). I have no use for the room and want the cheapest solution to safely solve the leaking issue. Can I just seal off the room with a block wall connected to the rest of the block foundation? If so, what kind of contractor would I want to talk to?