It is a Post Tension Slab... I am less than 2 miles south of my old house... and on the other side of I-35 (3 miles tops from my first house) I didn't have a single problem like this in my last house and it was post tension also.
I am worried cause we have less than 10 people living in this subdivision and I talked to a person on the other "end" of the subdivision and he is having worse issues...
Based on all the links I gave you, shrink-swell is a known problem i Texas and there are a number of things that have happened that make it possible that you can get some sort of both structural and financial relief. Texas Homeowners Association seems to be the place to start. You probably also need to make a trip to the local planning/zoning office to see what they have on the books re: requirements for foundations and for soil tests to determine what type of fdoundation is needed.
A quick read says post-tension slabs are not suited to shrink-swell, but I might have missed something so do not take this as gospel. OOPS! Re-read stuff & that is one of the recommended ways to go.
Contact the county engineer and the building inspector's offices. Verify that all he "i's" were dotted and the "t's" crossed by the builder, both for permits and for building code compliance. Verify that a building inspector actually was on-site and inspected everything.
Contact your homeowner's and title insurance companies and not only ask them for guidance but for steps in filing claims based on fraud by the builder. Make them see that they could be buying your house from you and financing you into a new one that is compliant with codes and laws.
I put in a link to a commercial outfit that says they deal with fixing these sorts of problems. Discuss with your homeowner's insurance about them hiring them, or a like firm more local to you, for an independent analysis and cost estimate for any repair/remediation work. Remind them that they can recover the expenses from the builder if basic construction errors, code/permit violations, or fraud are discovered, as opposed to merely getting your place fixed.
If nothing else, pay a commercial outfit to inspect/analayze on your own dime and then go after recovery from homeowner's insurance.
From what you are saying about the neighborhood in general, it sounds like you have a pretty good case on your hands. Again, go see what Texas Homeowners Association has been doing about the issue & see about following their steps.
Keep us posted.
stay safe.
skidmark
edited to correct my poor reading skills.
And once again to correct my bad typing.