I had my home inspection yesterday and the inspector noticed some rotting underneath the clapboard siding (pretty bad in some areas).

Apparently clayey soil is the root of the issue and the downward pressure of the house caused the rear stem wall to rotate laterally 1/2 inch and sink 3/4 inch.

Most of these houses have hardwood floors (sometimes under the carpet) do you know if there are any underneath?  

That said, not every subdivision is built the same way and not every piece of land in Texas is prone to expansive soils.  

It rains a lot here and we have clay soil.  

However, on top of that electrical issue, the ground is sinking in very noticeably around the area where the pool was filled in, meaning the backyard may need additional work and the soil itself that was used may not hold grass or vegetation like the rest of the property.  

Tile floor, tile shower surround, soils wood vanity.

Meaning, I wouldn't take a bank owned property for sale at $300M and offer $200M because you don't like the color of the front door but if you say, "Please see my roofing estimate at $25,000 based on inspection that shows this roof is at the end of its economic life and, please see the pool estimate of $25,000 that shows i will need a contractor to excavate and relathe and resupport the entire pool because of the engineer's report of settling soil and please see the $50,000 estimate for the toxic waste cleanup that showed up in the phase one environmental impact study so, in conclusion, i'll give you $200M cash".

@J Scott - Working now with a Land Surveyor for soil tests and they help with land division proposals as well.

Tiles usually crack on the spot that a concrete cracks after the fact, or are hollow by the touch, and it will be a problem until the house settle for good (depend of the soil and compaction etc, it can take over 15-25 years from the original construction).