Point: loose bolts (very old toilets have 4) will allow a toilet to wobble - if lifted.
If it wobbles without lifting, either the bottom of the toilet or the floor is not flat.
The only time a toilet should wobble is immediately after being seated on the wax ring. The installer removes the wobble.
It really should not re-appear.
IOW: look out for dry rot around the toilet - the old wax ring can fail, allowing water to leak. The caulk seal around the perimeter can hold the water under the toilet - so it is never visible, and a loose toilet is the first indication you have.
My first house was built in 1918 - the wood under the original toilet was rotted.
If this is an Old House that was a flip, be extra cautious.
House flips are pretty common where I used to live. Most of the housing stock was very old, and the houses hadn’t been taken good care of. Some of the flips are done well, but a significant proportion aren’t.
The electrical can be an issue. Did they fully remove the old knob and tube? This becomes an issue if they improperly splice things to the older wiring.
Did they properly insulate or was this a purely cosmetic flip? Did they change out the old plumbing or did they just cover it up?
I think we can safely assume that the inspector would have noted noted visible wiring defects.
Knob and tube is not necessarily dangerous - it is not grounded, and the hot and neutral are not as easily determined, but they are still insulated copper conductor (beats the hell out of damned aluminum).
I left the switch wires (was not going to rip out plaster and lath for a light switch) and the doorbell (and the unused buzz-box) on knob and tube.
You may be amazed that hardware stores in SF still stocked knobs and tubes well into the 90’s, it not past.
Minor update: It turns out the wooden columns in question are definitely not original, they’re just holding up a part of the floor. They were added recently. Fears ensued, on finding this out, that there was some kind of sagging or rotting problem. But there is no kind of rot or anything apparent in the section of floor in question. The structural engineer who looked at it believes it may have been placed there to hold up a waterbed (it’s under a bedroom) but that’s just his guess. The columns could simply be removed, or replaced with concrete blocks. Easy-peasy, apparently, to hear him tell it.
BTW it seems like everyone I’m talking to (including some of you here) are assuming that termites don’t, or are much less likely to, climb up concrete to destroy wood above? Is that the case?
That is the assumption. The earth/wood rule is about termites to some extent, but also to dry rot - holding moisture against wood will cause it to rot.
If the original construction is in good shape and of adequate design, the extra wall is unneeded.
I’d say the waterbed guess is probably the most likely.
You may, however wish to be present when the wall is removed - see if anything shifts.
That is true. And when they do climb concrete, they make little dirt tubes to crawl through to avoid exposure to the outside world, so they’re easy to detect and deal with.