I see alot of these around south Manchester. Once they start going, slapping some more paint on doesn't really work. This one had to be scraped back to where the stone still had some integrity. Then I applied a 3 part epoxy mortar with some braces to get a good shape as it cured. This stuff is tough, cures fast and is sticky to work with so make sure you have gloves and a mask! Or just get me to do it.