Painting external cement plinth

[RayPeck]

I think I am being paranoid, have been asked to repaint a external rendered plinth, it is suffering from some blistering which will come off with scraper ( tried one bit and exposed loads of woodlice) I think the blistering is caused by damp. If I scrape off all the loose stuff what should I seal/stablize the exposed bits and I want to use Dulux Weathersheild exterior paint either textured or smooth, how would I reduce the scrapped areas showing up. Any advice would be gratefully received

 

[Zampa]

Scrape off the worst and rub the edges down..give the whole area a coat of alkali resisting primer then you can either fill the bit where the paint has come off with exterior polyfilla or similar..(add a drop of pva to the water to make it more durable but down overfil because you wont be able to rub it down) or just paint over it with a couple of coats of masonry paint..pliolite based stuff might be better though

 

[RayPeck]

Is that just the area exposed or all the painted area, I am assuming that I would be better off using textured masonary paint, thinking of using Wikes Mastercoat, someone else said the put stabilizing solution in with paint as well!!