Rain after sand/cement rendering

johna

New Member
How long of a dry spell is needed after sand and cement rendering on the top coat? The scratch coat was done in good weather and now lots of rain is forecast, but the are some dry gaps.

The work is on a small patch repair, less than 2 sq metres.

If the wall has some natural shelter and it's not likely to face driving rain, is it OK to put the top coat on if there is a gap in the rain of say three hours? That's long enough for the render to firm up, but can it handle light rain at that stage?
 
How long of a dry spell is needed after sand and cement rendering on the top coat? The scratch coat was done in good weather and now lots of rain is forecast, but the are some dry gaps.

The work is on a small patch repair, less than 2 sq metres.

If the wall has some natural shelter and it's not likely to face driving rain, is it OK to put the top coat on if there is a gap in the rain of say three hours? That's long enough for the render to firm up, but can it handle light rain at that stage?
Such a small area , use a brolly lol
 
But how long do I need to stand out in the rain? If I stand out there with my brolly for too long, my neighbours will call someone to send me off to the funny farm.
Lol best to be prepared mate , piece of ply on a couple of legs leant at an angle , or similar
OK for downstairs , if its too awkward then wait ,
 
Is the base coat waterproof? If it is then 3 hours won’t be enough if the air is damp. For only two m2 I would put plenty of Wickes accelerator in.

Is it plain rubbed up rendering? If you have an I bar put it on 2mm too thick and when it starts to firm up use cardboard or paper to absorb the water out of the surface a bit then I bar back to flat. Within a few minutes with air getting into the surface you should be able to rub it up.

If the scratch coat doesn’t have waterproofer in then still use Wickes because the scratch will have absorbed moisture out of the air but wet the perimeter down on the wet to dry joint.
 
Just getting it done sounds like the way to go. It's a pro job turning into a DIY one, with me as the DIY'er. The bloke who put the scratch coat up has gone AWOL and I don't think that it will be finished by him. I have done internal, solid wall plastering with lime render and I think that I can get a reasonable, sponge finish. It's just a bugger that the weathers turned.
 
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