Cracked house foudation. My daughter has the polished concrete floors in her house and I have watched a crack?

You may be the victim of A sub par materials or poor workmanship B Your daughters home was built on Marshland , liquid faction or sometimes called quicksand sandy soil no solid soil to support the weight of the home E.G Playa vista a part of marina del Rey was built on marsh land Or swamp land first thing to do make sure you are not on a slab and have a foundation then do some Internet research to find out more about the area whether it is marshland then contact a reputable contractor that deals in foundations " specifically" not a contractor who says yes I can fix it this is not an easy fix nor a one or two day quick fix the house is sinking slowly but surely. One other thing to check into the housewares not built on an old oil dump site by refineries . Best of luck to you.

It's dis-heartening. How old is the home? Check the deed and builder's guarantees. Call a foundation repair company. Cover the floor with carpet. Don't look at it. Sell.

Not nec. sinking, settling and shifting due to a very poorly done preperation of ground before cementing.. Good Luck.