rendering

[wallmaster]

i rendered a house and 2 pannles have blown and have hair line crackes. I mixed the scrach coat and the 2 coat with the same mix raito how ever i didnt wet the wall in before applying the second coat and this day it was about 20c but well shaded. I have got to re render the pannles how can i prevent this happing again

[Mick Leek]

Depends on what you are rendering, But rule of thumb is as follows

Mix, scratch coat, 4 sand 1 cement 1 hydrated lime
Mix, top coat 5, sand, 1 cement 1 hydrated lime.

Its important the top coat is a weaker mix as if it isnt t will pull the scratch coat off resulting in it all coming off.

Dont forget the waterproofer and if has been very dry, wet the wall..

You could also try painting the wall with SBR before you start. Its a latex based adhesion promotor

Good luck