Painting new render.

No, but if you're looking to avoid it, or future re-painting, you could look at self-coloured silicone render such as K-Rend

used waterproof paint.

peeling off one year later. I have always wondered what it was that they di d wrong. Does anyone have experience of this?

I'd always use a pliolite paint. Expensive, but trivial in the big scheme. I can verify its longevity on an exposed SW facing wall

Well when they did my wallboards, they first knocked off the blown render, replaced it then sealed the joins with some kind of darker coloured stuff, then they sprayed the whole lot with a special bonding layer of paint. It had to be done when there had been no rain for a time and left to dry well before applying the other coat. A few years earlier, I had a cowboy outfit do a part of my back wall with the same product and it all was coming off like dandruff two years on. I know they did the under coat just after it rained. So maybe its not so much how they do a job but when they do it as regards the weather. Brian

I think the main feature of the pliolite paints is that they can be applied in the cold and wet, important in industrial applications

IME, cement based paints seem to work best. I think the porousity of them stops water accumulating behind the paint,film,

I have always used alkali resistant primer then 2 coats of masonry paint bu t on small areas. I need to do a large area and it is going to be roughcast . The alkali resistant primer will be soaked up like a sponge and is very e xpensive. I am wondering if I can do without it.

ed in the cold and wet, important in industrial applications

I've used Dulux masonry paint & it's still been good 20 years later. At the other end of the cost scale lime paint lasted, I forget but after 10 years or so it was rather stained & needed redoing. It's espsecially quick & eas y to use.

The others I've used, pliolite & household gloss, have been less sucessful. Pliolite was the worst, flaking heavily after 2 years on sound concrete. F rom Screwfix. HG works reasonably well, but its imperviousness is a problem . That is probably true of dulux & pliolite too.

NT

Mmm. There are a lot of conflicting experiences here that makes me think that it is the render that determines how long the paint lasts. Maybe not dry enough, too much lime or something?

Call me old fashioned but I don't trust water based paints for critical applications

Rednadnerb posted

We used ordinary Sandtex masonry paint, which has now been there for three or four years without any sign of flaking. We let the new render dry for two years before painting it.

That makes two of us.

And I have a strong suspicion that, like many so-called "eco" products (*), water based paints have the opposite effect to that desired. Because they are useless, they have to be redone much more often, so although they may have (say) 50% less environmental impact (including manufacturing them), they have to be redone 3 times as often.

(* Like water-saving toilets that have to be flushed 2 or 3 times to make the poo go away.)

FWIW the concrete I put the pliolite on was over a century old & as solid as rock. And it was scraped & cleaned totally before painting.

NT

I think it's mostly about how you manage to catch it, but then I read the subject line as "Painting new reindeer".

I'd say you've been very lucky. No masonry paint I've used here has lasted even half that long.

I'm certainly surprised. But equally surprised by the pliolite.

NT

I'm interested in why you left it for 2 years before painting. Was it intentional? or you just didn't get around to painting it for 2 years.