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Basement Wall Efflorescence and Insulation

vegas588 | Posted in General Questions on


I have an unfinished basement in CT that we are looking to get finished. There is some water intrusion and we are working on installing an internal drainage system to a sump pump that will take care of that. However, the walls do have some active efflorescence on them and was wondering how that should be handled as we prepare to install some rigid foam board onto the walls. I am thinking of using something like the Foamular 250 product. Also, the internal wall has some kind of skim coating on it. In certain areas near the floor, that coating is deteriorating. Should we break that all off and replace it with some kind of hydraulic cement or similar too? Thanks for your input.

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  1. Expert Member
    BILL WICHERS | | #1

    Your first step to be to make sure the water isn't getting in in the first place, which is best addressed from the exterior (perimeter drains, grading). Once that's done, you can insulate the interior. The efflorescence probably isn't a problem unless it's severe enough to make the insulation not fit flat against the wall, but you can remove it with special cleaning solutions made by companies like Drylok (the same guys who make the waterproof paint).

    It's difficult to say what that coating on the interior is without a picture.


  2. vegas588 | | #2

    An exterior drain might be possible on the one wall, but would likely not be on the others as it would be too expensive. The ground topology probably would not support that too much either, so would require a sump pump. However, interior french drains are possible. Photos attached of the worst area by the door. The rest of the basement walls are not broken away like that, but do have some surface efflorescence.

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