I understand the principles and practice of putting in a basement perimeter drain... but I've got a slightly irrational paranoia about the concept of cutting the basement floor free that way. Intuitively, it feels like I'd be removing part of the support for the walls... and these aren't even the fielstone and brick walls at the other end of the house; this is poured concrete, probably with rebar, so I'm sure I'm worrying unnecessarily.
Well, pretty sure.
I'd just feel better with a "yes, the floor is just a floor; stop worrying" consensus... thanks.
For what it's worth: The leakage isn't so much a general problem, but two specific sources -- somewhere in the bulkhead stairs enclosure or how it joins the foundation (coming in past the door), and from somewhere between the new basement of the 1945 extension and the bulkhead that stabilizes what was originally the back wall of the 1890 brick-over-fieldstone foundation. Of course the small sump pit is on the middle of the wall opposite both of these, so on the relatively rare occasions when I do get some water, it travels across the floor. I'd rather find a way to direct it to the sump and pump without making a mess. If the door wasn't involved I'd consider just trying to channel it, but.... This is starting to turn into another question, isn't it.