I'm moving soon to a new two-story house, built from concrete and AAC blocks (Autoclaved aerated concrete). The walls have an acrylic paint over them. I'm planning on installing a wall closet in the master bedroom (on the second floor) that will sit in a niche 60 cm deep and accommodate the entire closet. This will cause the closet to be flush with the walls, from floor to ceiling.

The wall behind the closet is an indoor wall, with the stairs on the other side. The ceiling is below the roof, which has a terracotta tiles covering with a crawlspace.

I'm worried about mold developing between the closet and the walls/ceiling behind it. The two solutions I've read about are:

  • Mildewcide paint - it seems that the mildewcide will eventually "run out", leaving the wall open for mold.
  • BioRid by Kefa - it looks like the only alternative, claiming to provide a permanent solution.

Does anyone have any long-term experience on either solution? Will Mildewcide paint be enough for a years long protection? Is this BioRid living up to the promises? Are there any other options available for preventing mold to grow behind the closet?

Edit: Currently there is no mold problem - this is a new house. But after tearing off a 15 years old closet in our current (30 years old) apartment and seeing the walls black with mold got me concerned. In addition, the weather here is very moist all year round, so it might be a problem in the future, and preventing a problem from occurring is better to handle it once started, no? Or am I being too paranoid?

  • Why are you concerned about mold? Is there a moisture problem, or a current mold problem in this location?
    – Tester101
    Commented Aug 29, 2011 at 12:07
  • I've updated the question with answer to your comment.
    – Eli Iser
    Commented Aug 29, 2011 at 12:28
  • How are you going to affix the wallboard to the brick? Firring strips? Commented Aug 29, 2011 at 16:50
  • @Karl - since the closet will be installed by the shop I've bought it from, I don't know. I think that it won't be affixed to the wall, but I might be mistaken.
    – Eli Iser
    Commented Aug 30, 2011 at 4:58
  • Ok, different meaning of "closet" than I'm used to. I was thinking a small drywalled room with a door on it, not a cabinet or cupboard. In this case I would probably just make sure that there are some small perforations in the back of the cabinet so that air will move in and out. Commented Aug 30, 2011 at 17:35

1 Answer 1


Mold needs three (or really four) things to grow: Stagnant air, moisture/humidity, and dim or dark areas with organic 'food'. The solution you're looking for probably involves using a permanent waterproof barrier (either a paint product -- which would be an industrial coating -- or a foundation product) in order to largely remove the humidity from the equation. Those coatings would need to be installed by a professional. As a cheaper and DIY solution, you might also consider 6mil plastic vapor barrier on the back side of the wallboard.

  • Okay. And what about condensation? If there is a slight gap between the wall and the closet, won't moisture condensate there? Will waterproofing the walls help with this?
    – Eli Iser
    Commented Aug 30, 2011 at 4:59
  • See my comment above; I was misinterpreting "closet". I would just make sure that you don't allow air to stagnate behind the cabinet; this will allow moisture to get out. Commented Aug 30, 2011 at 17:36

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