What effect would salt, salt water or ocean beach sand have on paintability of concrete?
If the salt is only on the exterior, from ocean spray, there would be little effect provided the surface were cleaned of any salt buildup before painting. Concrete made with salt water or unwashed ocean sand should be about as paintable as any other concrete. If, however, the structure is such that significant amounts of moisture can move within the concrete toward the painted surface, crystals might develop under the paint and disrupt the film. This could happen if moisture condenses within the wall or if water leaks into it.