I need to render an external wall. It's currently bare thermolite blocks (light aerated block) I'm thinking - Pva it. 5mm or so 4:1 sharp sand / cement mix Render mesh Another 5mm of the same mix over the top. All applied together (ie wet on wet) Is that the right sort of idea? I can plaster gypsum fine (I'm not a pro, but I've done more than one friends place also) and I'm fine with lime, but I've just never done cement render. Thank you.