I inherited my Grandmother's house and I would like to paint the basement walls. The paint on the walls now has peeled quite a bit from a water problem that was recently corrected.

Basically the paint has peeled from the bottom of the wall up to about 3 feet. I've scraped most of the peeled paint off but from there up the paint isn't that bad. However it needs to be a different color.

The walls are concrete block covered with a concrete parging. I want to paint the walls with Drylock. Do I need to completely strip the paint? or can i get away with scraping off the loose stuff, cleaning the walls with a scrub brush and cleaning solution and painting over the old paint?

Words of advice would be greatly appreciated.