Expert: Stephen Hayes - 9/25/2006

Question
the mold and mildew are on interior corners of the room.  There are no edges touching the outside walls.
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Followup To

Question -
My husband and I just purchased a house and are tired of the sheet vinyl in our laundry room so we pulled it up.  While doing so not only did we find 2 layers of vinyl attached to each other but also there is mold/mildew around the outer edges of the room and it looks like soap or something spilled by the door.  The floor is concrete however we are wanting to lay new vinyl tile and are wondering if we need to seal the concrete prior and how to get rid of the mold in the concrete?

Answer -
Dear Jessica;  Mold & Mildew are serious problems not only to your health, but to the building's construction.  That condition could be caused by spillages that seeped into the walls from laundry room spills, a problem with the foundation of the home, the original builder not putting down a proper ground moisture barrier, etc.  That type of problem should not be corrected by simply putting a sealer down.  Concrete is porous and always moves, so sealing a moisture problem from the top, may cause any latent moisture to not surface, but spread to the rest of the concrete, causing the entire installation to fail.  I suggest that your call in a knowledgeable general contractor in your area to see if you have a problem with the foundation, of the home, if a french drain is needed, etc.  Once the source of the moisture if found and fully corrected, new flooring could be installed.  Check the outside of the building's foundation opposite the indoor mold and mildew deposits to see if you find any indication of a moisture problem attacking the outside concrete.  What ever the reason for your problems, they should be addressed by a general contractor or engineering firm, in you area, who has the expertise to address the sources of mildew and mold.

Answer
Dear Jessica;  Moisture evaporates upwards and follows the path of least resistance, so just because the visual evidence of mildew & mold show in one area, does not mean that specific area is the source.  It could be coming from other areas and just manifesting itself in the visual area you see.  We still suggest that you just don't guess, but call in a knowledgeable expert such as a local engineering firm who would be able to do a proper moisture test by a couple of core drillings into the concrete, to see how far down the moisture is present.  A topical moisture test, such as a calcium choloride test, would not give you the proper results.  When someone's health is concerned, we feel you should find out, and correct, the exact source of the problem.  By sealing, you then force any moisture problems to spread and find areas where it can evaporate upwards.