My son bought a 8-year old house, last August, that had some new "plastic" flooring put in the basement over concrete in preparation to putting it on the market by the previous owner. I'm guessing that was done within three months of him buying it.

Just yesterday, we went in the basement and we noticed there is a crusty thing that 'oozed' up between some of the planks. Not everywhere. Just three or four places as shown here.

enter image description here

That image shows it being flat but one of the others is humped over like it had bubbled up. I ran my finger over it and it's a dry crust that just crumbled in place.

I don't know if that could be an adhesive or fungus/mold or even dog pee (he swears it can't be dog pee).

  • It like that goo from the ghost busters... on a serious note - that does not look good. Something must be reacting with humidity I suspect.. but the only way to find out is lif a few pieces and find out...?!!?
    – Piotr Kula
    Commented Feb 21, 2017 at 15:06
  • It's in the middle of the floor so lifting it is difficult.
    – Rob
    Commented Feb 21, 2017 at 15:11
  • It looks like expanding foam to be honest.. but why would it be oozing out now? Any why on earth would they put expaning foam under those panels? The only thing I can think of is that the foam didnt dry... long shot and now walking on it caused it to react and start ooozing out. But really.. Maybe you should consult insurance on the purchase agreement or anything like that.. You can just leave it and see what happens then sue the seller for a sh** job??! Donno
    – Piotr Kula
    Commented Feb 21, 2017 at 15:14
  • It wont be fungus or mold.. yet. dog pee.. :D hahah- Maybe but it would not cause it to bubble up. It really looks like a damp issue causing some kind of adverse affect with the adhesive, the plastic floor or something like that
    – Piotr Kula
    Commented Feb 21, 2017 at 15:16
  • The photo isn't very good. To me it just looks like some iron rust transferring through.
    – isherwood
    Commented Feb 21, 2017 at 16:30

3 Answers 3


Some vinyl planking, like mine, has a thin layer of corkboard on bottom to help padding. This is why orange-brown crust is seeping up. Moisture from slab is pushing thru the cork layer and forcing it up. In my case, just in very heavily traveled area in front of bar. Just scraped mine up with plastic dish scrubber and put some lemon oil on it after. Lasted 3 months and had to do it again. Cheaper than getting new floor!

  • Hello, and welcome to Home Improvement. Good answer; keep 'em coming! Commented Dec 11, 2018 at 22:13

Moisture moves from a cold environment to a warm environment. In your case, moisture is “transferring” (moving) dirt particles (and possibly colored pigment from the adhesive) up to the surface of your floor.

If it scrubs off easily, it’s dirt. If it’s staining the flooring, it’s pigment from the adhesive.

To check this, clean a spot as good as you can, then tape the edges of a clear piece of plastic down over the spot. If you see moisture under the clear plastic (don’t remove the plastic from the floor), then moisture is being drawn into your basement.

(The reason you need to place plastic over a known spot is because the moisture is coming from under the slab, there are only a few places where it can penetrate through the slab AND it is so small (minor) that it is dried by very little air movement.)


This is an odd issue. After some investigation, I found a similar problem on another website where a guy experienced this in his garage. It could be that there was too much adhesive / glue applied under the vinyl flooring, and after applying pressure on the flooring (walking on it, or even settling of the boards), this causes the adhesive / glue that hasn't fully cured to leak, or to shift under the board.

As for the coloring, I'm unsure what color, or condition the cement was underneath the flooring, but the adhesive could have "grabbed" the pigments or loose particles that were on the cement and carried it to above the vinyl. You should be able to use a razor blade to (CAREFULLY) scrape the glue off the vinyl if wipe off and it should look fine.

  • I'm hoping this is the issue. I remembered that one side of the floor goes into a hallway that has some carpet laid there. That can be lifted up so I'm hoping he can see a smear of similar colored glue or he can lift the planks up a smidge to look under it.
    – Rob
    Commented Feb 21, 2017 at 16:46
  • I hope so for your Sons sake. That doesn't sound like fun. If he has extra pieces of vinyl, he can lift up the areas where there are issues (which I'm hoping is one or two spots), and lay the extra pieces in those locations. I also found this article: familyhandyman.com/floor/vinyl-flooring/… that I hope can help. Let us know what happens. I am interested! Commented Feb 21, 2017 at 16:55

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