I own a 1350 sq/ft SFR in Maryland built in 1958. Walk-out basement on sloped lot.  The front basement wall entirely underground and the rear-most wall 2’ underground.  The visible CMU basement wall had numerous cracks in the parging, which I filled with either a cementitious mix or concrete epoxy in a tube.  I’d like to enhance the look of the wall and had two thoughts: 1)acrylic latex concrete paint and 2) concrete elastomeric paint.

I like the elastomeric paint because the product (BEHR @ HD) claims to be thick enough to conceal some cracks.  But my concern is that it is waterproof.  I worry about the following scenario.

Scenario – I paint the entire exterior CMU wall, which no longer absorbs or releases water water/vapor.  The ground becomes wet and the subterranean CMU absorbs water like a sponge.  Rather than that water eventually making its way to an exposed wall via capillary action and evaporating, it stays in the wall. 

The interior of the basement wall is either ccsf or taped XPS panels, so it can’t easily evaporate into the house either.  Before I finished the basement (which included an interior French drain) there was fluffy efflorescence on the concrete walls.  So while I hear that concrete can stay wet, I’m a little worried about minerals leaching out of the CMU or just supersaturated walls constantly challenging the interior basement.

I would love to hear suggestions from the community.  BTW, I would love to excavate, exterior waterproofing, etc., but it’s not in the financial cards.