Black patches on interior foundation

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Posted by: from Pincourt
1/16/2012 at 12:10:31 PM


We are planning on finishing our basement. The previous owners had installed white Styrofoam on the top portion of the interior foundation walls. When removing this there are some spots (as much as 2'x2') with black on the surface. All black areas are above grade and the wood resting on the foundation appears fine (no wet stains and no black).

Is this mold? Can mold live on concrete? Can I go ahead with framing?


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Date/Time1/16/2012 at 4:00:41 PM

Mold can't live on concrete, it needs organic material like wood and paper to grow. They used to use a black glue to hold white styrofoam to concrete.

Could it be that?


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Date/Time1/16/2012 at 4:23:09 PM

Yes a black glue was used. I suspected that but the effected area is larger than the glue spots. Could it seep? There are definite water drip marks. Maybe a condensation problem?

Thanks for responding so quickly!

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Date/Time1/23/2012 at 7:17:47 PM

Condensation could be possible and maybe bled the glue, but the moisture must have been pretty high and sustained to get staining.

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