blown exterior render

[dbdiy]

I had very patchy render on 3 exterior walls. A thickness of about 3mm had come away in small to medium patches all over but been painted over. I had the whole wall re-rendered but was never convinced it was done very well. It was done in very hot weather. I thought it was odd that the thickness of the new render was only about 2mm thick. After a few weeks I used stablising solution and then painted it.This showed up what a bad job it was. Then 2 weeks later it started blowing.

I got someone else to come out and repair the blown bits. He said he used weathershield filler. I let it dry and then repainted it. (didn't use stablishing stuff that time tho) but it has blown again. I've spent £500 and the wall looks as bad as it did before but I also now have open blown render.

Any advice about why it now blowing and what can I do. There is no pattern to the new blowing and the original patches. All I can say is that it is these repaired bits that keep blowing. I asked the guy who did it why it is happening but he doesn't know why.
Help!

[misterg]

Hi dbdiy

I was once told by a builder you need to let the walls dry out. If the bricks have absorbed water seeping behind blown render, new render won't stick very well to them.

Hope this helps.

Regards

G