Bathroom remodel in 1800's home
I live in a unit in a house built in the late 1800's. The bathroom is built about a foot and a half above the floor level of the rest of the house so there are steps to get in to the bathroom. I can't only assume it is because the bathroom was added after-the-fact and so as not to lose ceiling height on the floor below, the bathroom was built up so that the plumbing could be run under the floor. I would like to renovate my bathroom and make the bathroom floor level with the rest of the house. Is there a way to run the plumbing in the walls so that I don't have to raise the floor. Or, if I do need to keep it in the floor, how much height do I really need? A foot and a half seems a bit excessive.