Contrary to popular thought, tile and grout are not waterproof, and some moisture will penetrate even if sealant is used. ... However, if you choose to use concrete backerboard, which is much stronger and more durable than gypsum board, a water vapor membrane must be placed underneath it or a sealant applied on top of it.
What kind of paint do you use on cement board?
Acrylic paint is the best choice for cement board. It's especially important if you are working with new cement board to avoid oil-based primer. It will increase the roughness of the surface of the board. It can prevent the paint from adhering properly.
Can I paint directly on cement board?
Do not paint a cement board unless you have thoroughly cleaned it first, or you may have problems with adhesion. ... Unlike standard cement, which is not an ideal surface for paint adhesion, fibrous cement boards contain pores that soak in the adhesives within the paint, making the finish much more durable.