Im currently renovating my house, I've not long bought it and have just pulled up what looks to be 1970s carpet in my living room and before I put new carpet down, and build out my fireplace with a stud wall (there's going to be no fire anymore its just to cover the hole) the current floor isn't in a great state and I'm thinking of using self leveling concrete but don't want to have to pour it on all of the floors on the downstairs, do I have to do this or can I contain it to one room?