Painting masonry, when the surface is flakey and bubbled?

[OwlMother]

Our house is a 30's semi, brick built with a stone front. It's entirely painted white. The bay window at the front has a stone sill and the paint is badly flaking and bubbled in places. This is despite the fact that the whole house was painted two years ago.

Obviously the painter didn't prepare it properly, what should they have done? The rest of the house seems ok- presumably we can just do the front?

Mine is the same - painter was shit. I was told, by a different painter, that the problem may be that the front of my house is south-facing so gets hot which may make the paint bubble & flake more. I think if it was prepped properly, it wouldn't be so bad.

I'd just re-do the front of yours.

The stone sill probably is damp. The water trying to get out, and the crystals of dissolved minerals, push off the paint in bubbles. If you scrape them off you will probably find powdery crystals behind.

If you can locate and repair the source of damp, the paint will last longer next time. It may well be getting in round the window frame.

Stone is a breathing material and is better unpainted.