Moisture damaged vinyl floor tiles under carpet

I'm early in the process of re-doing the basement in my 1950s' era home. The original owner put a padded wall-to-wall shag carpet over the floor. This carpet could have been sitting there for decades. I rolled it up to see what was underneath and found tiles which have what appears to be dirt around some of the edges. I'm assuming this is the result of some kind of moisture damage that occurred over many years. My guesses are that this was caused either by moisture in the basement air having condensed on the colder tile surface, or from water vapor under the slab having migrated to the surface and condensing.

In the six years I've lived here there has never been any standing water that I'm aware of in the basement. And this was during an era of record breaking rainy seasons. I do need to keep a dehumidifier running during the warmer weather or else I'll get a musty smell.

I'm aware these are nasty 9X9 asbestos tiles and that is a whole other huge topic I'm not going into here. I'd just like to have some clue as to what happened here.


Here is a close up of a tile. The 'dirt' material is raised up slightly maybe 1/32" high.
Tile before cleaning

Same tile after cleaning with a a water ammonia solution.
Tile after cleaning

The 'dirt', or whatever this stuff was, wiped off easily. There are indented areas in the tile where the material was removed and the tile material in this areas is crumbly (I'm well aware of the dangers of friable asbestos materials).

Anyone seen something like this before? And did you have any idea what causes it?

I'm hoping that regardless the cause I'll be OK with putting DriCore over this floor and then putting low pile carpet on top of the DriCore. Any opinions on that?

Thanks.

 

If the old carpet you took up shows no sign of water/moisture damage and if you have had no standing water in 6 years, I would say that you would have no problems if you put down DriCore and new carpeting. I'm not an expert but I do have a home that was built in 1954 and came with old asphalt tiles on the basement floor. With no standing water ever observed, I put vinyl tiles over the old asphalt tiles and eventually a wall to wall rug. It's been quite a few years since then and the rug and floor are still fine with no moisture problems. I do keep a dehumidifier down there just like everyone else on my street.

Ken

 

It is possible that the material around the edges of the tile was created by some minor moisture mitigation up thru the slab. It does not appear as if this is a big problem as long as you utilize the dri-core as you propose. Sometimes what you see at the edges actually turns out to be old wax that has been bubbled up and broken down by the moisture over time. Good luck with the renovation.

 

I'm in the same boat as you. There are other products that are less expensive. I'm leaning towards Delta FL or Super Seal. Someone suggested I google "problems with dricore". Very interesting. Keep in mind that I have zero experience in doing this and I was totally sold on the Dricore but now, I'm going in another direction. If you search these forums, the majority of the people who have used the dricore are very happy with the product. Good luck. I'm sure you'll be fine either way.