I have an ICF foundation on my home that water is penetrating. I don't have a sump, and I don't know what kind of drainage is installed. My main concern is my west wall, since it is in the finished half of the basement. The sheet rock has become damaged and moldy, and I know it is a problem because my allergies will kick in if I spend an hour down there in the summer. I know I need to remove the sheet rock and kill the mold, and I need to fix the drainage on the outside of the house.

What about the ICF on the inside of the house? Would it be enough to just spray it with a bleach solution? Or do I need to remove the ICF and reinsulate to eliminate my mold problem?

  • I take it this is "traditional" ICF, with foam panels on either side of the concrete, connected by plastic spacers to provide rigidity during construction? – ThreePhaseEel Feb 29 '20 at 0:39
  • Bummer I love ICF forms they save a lot and provide great insulation. I would try to make sure the foundation drain is clear if it was back filled with dirt it may have plugged up. For mold I use 3% hydrogen peroxide and water , it kills mold and mildew without the stink of bleach. – Ed Beal Feb 29 '20 at 1:29
  • @ThreePhaseEel Yes about 3" thick, and in the shop area the plywood on the walls is screwed right into the plastic, so I'm guessing the sheet rock is the same. – rtaft Feb 29 '20 at 11:03
  • @EdBeal I plan to dig up that wall this summer and add some air gap foundation wrap as well as checking out the drainage. – rtaft Feb 29 '20 at 11:11
  • Did you ever get this resolved? If so, please give a check-mark to the answer that helped you the most, or write up your own answer explaining what you did to get it fixed and give yourself a check mark. That will help others with this kind of problem know that this has a resolution and is a good place to look for their answer – FreeMan Jul 28 '20 at 17:17

My last place I built my shop with icf, 1 wall is 11’ below grade, I used foundation drains and back filled with river rock, this is on a very steep hill and below the shop we have a French drain in front of the entire house , these drains flow an amazing amount of water , the 4” pipe full flow after a day or so of rain. So if you can dig it out and add drains then backfill with rock there will be nothing to hold the water on the wall then the drain will remove the water. I have used this process on many houses with sub grade walls and only 1 ever needed additional sealing and it was cinder block. Providing the water a path that doesn’t hold water and getting rid of the water at the bottom usually works well. Then there is no moisture to create the mold. I use 3% hydrogen peroxide and water to kill mold it works really well and doesn’t stink.

  • I’d be careful using hydrogen peroxide on ICF. It could cause it to dissolve. It’s good on plastic, etc. but not on styrofoam. – Lee Sam Feb 29 '20 at 18:23
  • So you are thinking I should just spray it and I don't need to remove it? I pulled off the sheetrock which was attached directly to the ICF. The mold appeared to be limited to the sheetrock. There is floor edging for the water but no plastic sheeting to guide the water into the edging. The outlets are in the ICF and water is getting into them. – rtaft Mar 2 '20 at 14:02
  • Yes a spray with a weak solution 3% will not harm the the styrofoam. It will kill the mold, mold needs food, styrofoam is not a food source for mold. The paper from the Sheetrock is a food source especially with dust and other debris, so even if the mold is removed if dampness continues it will come back. The one thing that most don’t know is there are hundreds of mold types and few are toxic to us. What we use to kill the mold usually bleach or hydrogen peroxide in consented form can be more toxic to us so make sure to wear gloves and glasses at a minimum when cleaning up. – Ed Beal Mar 2 '20 at 14:20

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