Painting window sils

[oph]

Afternoon all,

Ok looking to repaint my window sills at home. House built 1884 and is a victorian mid terrace. The sills are concrete/ render finish over brick with tiny bits of aggregate in it. Most of the paint has scrapped off but should I use a hot air gun to remove the remainder?
Also, do I need to prime it before recoating it?

Any paint suggestions?

Thanks

 

[dcdec]

A water based masonary paint is what i'd recommend as it will allow breathability, oil based paints will crack. Bedec masonry or their MSP would be my first choice, failing that a branded trade paint like Dulux. Thin the first coat by around 25% on a bare surface then two further full coats.