I just pulled up my carpet & found some hairline cracks (less than 1/16" wide) in the slab. (Floating slab on soggy Louisiana soil; no pilings that I'm aware.) I followed the cracks and each one terminated at a small piece of plywood (4"x4") nailed to the slab. Is that some sort of foundation repair? I've had the house (& carpet) for 12 years; so, it's obviously older work. And, no, nothing was revealed to me at time of purchase. And, no, I had never heard of a home inspection at the time.
I have always had problems with a couple of sticky doors when it rains & some ugly cracks have appeared; but, when I got 4 different foundation experts out five years ago, they said my house was level within fractions of an inch ... general consensus was that the cracks were from bus and truck traffic & the $20,000 foundation repair that half of them recommended was only "preventative" (the other half recommended doing nothing, which I gladly did). Surprisingly, none of them considered the 3 oak trees to be a problem for anything other than the sidewalk!
I'm just trying to figure out what I'm looking at and if I need to re-explore the foundation repairs to address my sticky doors and cracked walls.