I have a small section of wall (50sf) where the stairwell goes into the basement that is CMU (concrete masonry unit or concrete block) painted with at least an egg shell, possibly even semi-gloss.

Where the CMU from the basement level meets the textured drywall at the main level, the drywall overhangs the CMU by 1/8" to 1/4".

I was thinking of skim coating the CMU then matching texture and paint so it appears like drywall all the way to the basement floor.

Is there a product that can go over the painted surface to make it ready for a drywall skim so it sticks? I figure sanding alone will not be enough due to the "rough" or "bumpy" surface of the CMU, the sandpaper won't make contact with the low areas.

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1 Answer 1


It should be fine all on its own, but if you want to be really really totally sure, just sand a bit to expose some of the CMU surface in the high areas.

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