My family is moving into an old house, built in the 1930's. It is a cape style house, which is common in this area. Anyway, the room I am staying in is built directly over the garage. My guess is that the house was built first, then the garage, then the room over the garage, since there is a place in a corner of the room where the exterior of the fireplace is visible and also part of the siding.
Anyway, the room at one corner is about ~2 CM lower than the rest of the room, which is generally uneven. If you look at the garage and the room from outside, the garage's concrete face is even while the siding above it ( my room ) is sloped downwards noticeably.
I'm guessing the only way to fix this is to rip up the existing hardwood floor and place shims in the sleepers and subfloor.
What I am asking is, is there any chance of the floor sagging even more? What should I do about it then?