Can anyone give me some advice on how I go about painting on top of lime wash? Part of my external wall is lime pointed stone, (random stone). It was lime washed a few years back (with about 4 coats of "St Astier" paint), which I'm not too impressed with. I'm wanting to paint over it with a modern breathable paint, as I do not have the patience to do lime wash again. (The rest of the house is concrete rendered and its got modern paint on it.) Is there anything I should do prep wise? I was thinking that taking a wire brush to it would do the job, as the lime wash just looks like somebodys sprayed coloured water onto the stones and pointing! Any advice would be greatly appreciated.