We're still in the planning stages, and one thing that was worried me is our expansive clay soil. I've done some searches on the forum here, and there doesn't seem to be a clear consensus on it. We built our house 4 years ago and had a soil test done then (trying to get the test results from our builder). The slab engineer recommended a post tension cable slab, and for the most part it has worked. We've had a few small surface cracks here and there in the garage and back porch, but no doors/windows sticking. I've spoken with three PB's so far and their opinions are as wildly varied as their opinions on SWG (a whole other topic).
PB #1, located about 70 miles away: "We always put in piers in your area. It just standard practice for us around here with your type of soil."
PB #2, located same city as PB #1: "We do piers sometimes if you have really bad soil. Get me a copy of your soil test. If the expansion is above X.XX then we'll most likely do a few piers. The gunite shell is fairly solid and will be tied into the pool deck via rebar."
PB #3, located about 60 miles different direction: "We put in 1/2" rebar, tie it in to the pool deck, etc etc etc. We guarantee our gunite shells for life. That thing isn't moving."
So far PB#3 has probably built the most pools and I would say has the most experience, and he's most likely the PB we're going to go with. However, I've seen the nasty effects of moving soil in my parent's two houses they've built. The first one was on expansive clay soil (worse than ours) and they had to spend tens of thousands of dollars with a slab foundation repair company to fix it all because the builder skipped town. Driveway sinking 4 inches from the garage...doors sticking...leaks in slab..etc. So, I'm especially sensitive to these issues and for the amount of money we're about to dump into our "backyard oasis" I want to make sure all bases are covered.
Anyone have any experience with these types of issues? For the most part, I can't find a ton of info about it...so that makes me thing it is much less of a problem than expansive soils with house foundations. I'm thinking it might be worth it to try to find a engineering professional to give their independent professional opinion.