The 7.5% will be calculated by TurboTax. The expenses would be entered in the medical expenses. That would be the total cost for the construction of the pool. I am not sure why you need appraisals. Please explain in the comments.
If you want to read about how a pool can qualify as a medical deduction, this is well done by Julie:
https://ttlc.intuit.com/replies/6488660
