Here's a tip I learned when I retired to the WCape from Jhb ... and for years in Jhb I spent a fortune on expensive products like "weatherguard", "wall n All", "double velvet" and the like.
Buy the cheaper Plascon 'Roofseal' (
http://www.autospec.co.za/productme...ducts/waterproofing/plasconroofsealwrs1-5.pdf ) for much less that the so-called 'superior' PVA paints.
This entire town only buys plain white Plascon 'roofseal', and then adds the required colour tint, to paint exterior, & interior, plastered walls. It has excellent coverage, and dries to a smooth matt finish
It's a PVA paint, and is as good, if not better, than all the fancy-named brands. It's designed for roof painting, and I figure that a any paint cannot get more severe exposure to weather than up on a roof.
The only tiny negative is that it is not one of those modern low-odour paints, so a newly painted inside room may smell of wet paint until it dries.
I have no, and have never had any, involvement with any paint manufacturer or supplier. I'm just sorry I only learned of that product 2 years ago when I left Jhb to retire in a small WC Town