Yes, Brian, I was referring to the wood faming apparently being below grade in the rear. The ground was snow-covered and frozen, but this was apparent from lifting a bit of the siding on the side of the addition where the elevation was a bit lower. At least the framing appeared to be treated lumber.
Yes, I do recommend digging a swale in a situation like this. Lots of digging to be done in this particular case. I’m also recommending they check city records for permits, inspections, etc. with the caveat that passing a city inspection does not guarantee proper construction.
Being in Michigan during a January (very) cold spell, the ground was frozen so solid it would not have been possible to probe it with any sort of rod. There wasn’t any way to tell how the slab was constructed other than to check city records if proper permits were obtained.
My main concern about footings here has to do with the effects of freezing and expansion of the ground with the clay soils that are present in most of SE Michigan. These conditions wreak havoc on a lot of foundations, particularly the flimsy hollow concrete block basement and crawl space foundations that were common when much of the area was built up in the early 1950s.