I've got a window sill that appeared to have a piece of slate-like material on the top that had come away from the concrete sill and was breaking up. Not sure exactly what it was or how it was fixed but it all chipped off with no problem. This has left an unpainted sill at the top but the sides are still painted. Most of this paint is in good condition but a little has flaked off. Should I remove all this paint with Nitromors or just scrape off the flaky areas? I've filled up some small cracks on the top with Sandtex filler, so will be ready for painting. Saw stacks of Sandtex exterior paint in B&Q yesterday. Any preparation required for this, is it thick enough that it would smooth out the rough surface of the sill?
Dave