msgreatdeals, Thanks for your reply but I wish I read this first before sealing the 47 foot long crack (found some places were 1/4th & 1/2th but most of the crack was 1/16th & 1/8th wide)with flexible DRYLOCK masonery crack filler. Then I started to use the filler to fill in small holes in the three rooms but some of the bigger holes that were formed from removing the clumps of plaster that was not level or from removing the tackless would not fill so I went in the garage and found some cement filler that my friend used to fix the step going from the garage to the middle foyer. I wish I used this only for the holes. I hope I did not mess up. The installer has not called me back and I want him to arrive tomorrow ready to install the floor and not fixing the floor and not being able to finish and then the project dragging into next week. msgreatdeals, thanks for sharing about your concrete floor also. I hope your floor will be OK also with your epoxy repair. I did have some water damage from a leak in the Poland Spring Water coolor about 10 years ago. that is where the crack had started. I forgot about that! But all in all my concrete floor was very dry. There were fine cracks in the concrete floor in other places but they were small but I still used the sealant that is flexible to seal them also.

How large is a "fine crack"? A photo would be helpful. The saw cuts are control joints that do not go all the way through the slab and are intended to encourage the inevitable cracks to form there instead of elsewhere. An expansion joint is a separation between slabs to allow differential movement. Its impossible to know if the slab was poured properly but I suspect a high water content, poor curing efforts, insufficient reinforcement, or hot/dry/windy weather. If this is essentially a cosmetic issues, it should only matter if the slab is exposed.

ok, there where no peers install. Its a post-tensioned structural slab with no peers. I large 1/8 crack development when the framers did their thing. The tensions weren't tightened before the framing was done. Some people say it should have been like 5 days after the pour and before the framing. Dont know if that is why the crack occurred. But it has. I did hire a structural engineer and take grade levels and he has and he will after it had been tighten, which was done today... It is the structural engineer that is says because of the crack or failure in the foundation, he might recommend peers now. before tightening, his measurements showed the center on the garage were the crack occurred as about 3-4 inches lower than the outer right and left edges. So it might be showing signs that the center has fallen. This MAYBE a need for peers for long term stability. That is were things are at now. Just trying to get the best info I can get to know what to do here...

Building on millworkman’s comment, epoxy will not prevent cracking. Generally score lines in the slab control and disguise crack locations but not always. We installed an inter-locking floating vinyl garage tile on ours.