Hi, could anyone possibly advise how I can fix this please. It is crumbling, and I’m not sure how to go about fixing it? Any help would be really appreciated.
I chop out the blown stone, make sure there's a key into what's left with holes and/or epoxied in stainless rods. I then make a 'plastic stone repair' using NHL and a ginger sand (or stone dust) 1:3, moulding it carefully to shape. It can be rubbed as it goes off to get something close to a natural stone finish. I've got unpainted Doulting Stone that's done this, but that paint won't have helped.