I recently removed my basement drywall and the old insulation behind it. The basement was first finished about 30 years ago (by old owners).

The walls are concrete blocks. Most of them are fine, but one corner clearly has some moisture issues and some mold. This is near the only part of the house where the soil isn't well-graded outside so the location makes sense, and I'm going to fix that.

I was planning on re-painting the walls with some Drylock paint and also some anti-mold paint before having the walls spray-foamed (with closed cell foam).

I've had a lot of luck with this anti-mold paint on bathroom ceilings. I painted one five years ago and the ceiling still doesn't grow any mold.

Does it matter whether I put the Drylock on first or the anti-mold paint? Does the Drylock have to go right up against the concrete and get absorbed or something like that?

  • 1
    I'd be inclined to think that simply sealing the concrete will mitigate the mold. I'd do the Drylok and see what happens.
    – isherwood
    Commented Aug 15, 2017 at 15:36

1 Answer 1


It looks like the Drylock FAQ covers this and I missed it.

Q. Can DRYLOK® Masonry Waterproofer be used over paint?

A. Yes and no. DRYLOK® may be used over any other cementitious-type waterproofing paint in good, repaintable condition, either inside or outside. However, DRYLOK® cannot be used over an oil or latex-based paint on the inside of a building. DRYLOK® will adhere to these paints, but if it cannot penetrate into the pores of the masonry itself, it will not waterproof the surface.

and also:

Q. Can you paint over DRYLOK® Masonry Waterproofer? If yes, what is the procedure?

A. Yes, using a good quality 100% acrylic latex paint. DRYLOK® Masonry Waterproofer can also be tinted for a decorative finished coat.

So it seems clear that you should put the Drylock on first and then any other paint, including the anti-mold primer.

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