Hi All,

We live in an old house (probably around 100 years old) with the original hardwood floors. I'm not entirely certain, but I think they are oak. We've only lived here for about 2 years. Here in the Northeast, we've had several weeks of humid weather (hurricane Irene, followed by frequent rains and high humidity). I have recently noticed several (old?) stains/dark spots appear on the floor, they look like water-spots in the pattern of what a spill would look like, about as big as my hand or a little bigger. We haven't spilled anything on the floor, there isn't anything leaking from above (and the spots are in the middle of the room), and as far as I can tell from looking up at the floor from the basement, there isn't anything leaking under the floor either.

Is it possible that these are old water stains that show only in very humid weather? It just seems strange to have these dark spots appear out of nowhere, but perhaps they will appear/disappear over time with the humidity?

Could it be condensation from a hvac duct in the floor?

No - the house has no central air, and has steam/radiator heat (but there are no pipes under the floor area where the spots are located).

I took a photo of the floor, but I'm trying to figure out how to post it ...

Talk to your cat.....

IF the floor is sealed with some kind of urethane, spots wont normally just happen.Something has to penetrate the flooring from below or above.IF the floors don't have much finish on them and you happened to clean with something harsh, that may have caused the spots to appear. But it's hard to say without actually seeing them.

Well, central air would significantly reduce the amount of humidity in your home. However, I am not sure that such pronounced spots would occur with humidity. It is possible that something was spilled there before you owned it, or someone did a spotty job on the sealing of the floor. I know many remodelers go quickly over the hardwood floor, thinking that it can't be messed up, when in all reality it is easy to mess up. Good luck!

I'd definetly have someone check it with a moisture meter.