Re: Drywall over painted block
[QUOTE=Hank Bauer;248385]I would agree that skim coating is acceptalable I would stay away from the dry wall product and use an Acrylic Plaster applied to the block <snip>
I agree. These days there aren't many left who understand plaster finishes- it's different than drywall but is still very viable for purposes like this. Plaster will stand up much better and much longer here than a drywall mud skim. If it were possible I would scarify or sandblast the paint to get a direct bond with the block underneath- that way even if the paint underneath were to fail later on it wouldn't matter-the plaster would still be well bonded.
Positively avoid any drywall installed directly over masonry- I've [I]never[/I] seen it last as it should. The temperature differential with masonry always carries condensation with it; the question isn't "If" but "How much" and plaster, being closer to masonry's make-up than sheetrock mud, will keep the issue at the surface where it can evaporate instead of under the sheetrock mud where it will loosen the bond. While gluing helps hold drywall, if the paper backing on the drywall sheet comes loose from dampness it all falls down. Drywall needs to be fastened through the face as it was designed to be done; that way the entire thickness has to fail before it falls down.