So we've been in our new home for a few months now (built in 1950), and I've found that there is a 2'x2' hole in our basement floor, it was under a small pallet that neither we, nor our inspector looked under.
My first guess was that this was cut to access the sewer line, but then I noticed that there appears to be a concrete patch running the length of that wall, so maybe it's drainage related? The concrete floor only appears to be a couple of inches thick, and there is a rotting wood frame around the edge of the hole. Upon visual inspection I don't see brick or tile in the hole.
During our home inspection, we found slightly elevated radon levels, so we've been thinking about adding a radon reduction system, but now I'm thinking this is probably the culprit. I thought covering it with plastic might be the best bet--I'm thinking access to these pipes probably isn't a terrible thing. At the same time I want to make sure I don't create a situation that causes the pipes to deteriorate.
Anyone have any insights as to what this could be, or what I should do about it? I found the thread below that shares some similarities, but I want to be sure.