I have an older addtion to our home that was added around 1965 or so.The concrete floor was not done very well,it slopes alittle and it shifts around about 1" to 2" during the early spring and fall. Causing the sheet rock to crack.My wife has wall paper up, but it also sees the effects of the shifting floor.How do I fix it so does not shift? And would a floating floor be best on top of the concrete?