Hi Kate,

It sounds like you may have some damage under the top layer of cement. Perhaps some smaller cracks underneath are there, that you can't see. One problem that may arise now is mold and with mold comes mold spores. If you are alergic to them, which I am, they can really bring on allergy symptoms. Often you will see a white dust that shows up on top and that is actually mold. I had it in my prior home right along the hairline cracks in the garage floor.

Sounds like a serious problem though. You must be really disappointed since your home is so new.

Petra