Stucco direct onto vermiculite?

[di11on]

Hi folks,

I've nearly finished my build. I've done all 7 curing fires - no cracks so far thank heavens - but I did take it super slow thanks to all the advice.

I have a 1" layer of CF blanket on top of my cast dome and another 2" layer of vermiculite on top of that and I'm ready to Stucco.

Some questions:

1. Can I stucco directly onto the vermiculite?
2. How long do I need to wait between stucco coats?
3. How long should I wait before painting?

Thanks in advance

[browny]

Re: Stucco direct onto vermiculite?

3. The paint should have a recommendation. Typically I have seen 3-7 days for water based paints and 28 days for oil based. These are minimums and will be influenced by local conditions.

[david s]

Re: Stucco direct onto vermiculite?

1. I do it this way all the time.
2. I do one cement coat around 15 mm thick, wrap the whole thing in cling wrap for a week to compensate for moisture loss into the vermiculite layer.
3. Then fire away for about 10 fires, so it is really dry. (Any moisture left in the render layer can cause blistering of subsequent acrylic coats). Then give it a final acrylic render coat. Paint it later if you don't like the colour.

[di11on]

Re: Stucco direct onto vermiculite?

Thanks Dave - as always :-)

What is the "final acrylic render coat"?

I was going to go for a 5:1:1 (sand,lime,portland) mix for the first stucco layer and then 5:2:1 for the final render layer and then paint. Would I be better off with an acrylic layer (whatever that is?)?

Cheers

[david s]

Re: Stucco direct onto vermiculite?

Thanks Dave - as always :-)

What is the "final acrylic render coat"?

I was going to go for a 5:1:1 (sand,lime,portland) mix for the first stucco layer and then 5:2:1 for the final render layer and then paint. Would I be better off with an acrylic layer (whatever that is?)?

Cheers

Those recipes sound ok. each subsequent layer is meant to be weaker and contain more lime so maybe 2nd coat 6:2:1
For the acrylic coat get something that is known as elastomeric (lots of flexibility). Don't know what is available to you, maybe try a paintable pond liner or bathroom sealer.

[RichC]

Re: Stucco direct onto vermiculite?

..not meaning to hijack thread but I've got similar questions.
Can you elaborate more on the acrylic coat please David? Is this something thats mixed into the stucco or is it a 'paint on' product that goes onto the render.
When you refer to bathroom sealer I think of 'tanking kits'. Theyre like a rubberised paint. My shower walls were painted with a tanking kit before tiling to ensure no moisture ingress into the plasterwork.
@Di11on, congrats on your build, mines been a work in progress for over 2 years now(my wife slags me about it now and then) but Ive been cooking in it since last october I think. My plans have changed(improved) so much during the build that I'm very happy I didnt just build based on my original intentions. Each step has taken a lot of research and advice to get right
R

[david s]

Re: Stucco direct onto vermiculite?

[QUOTE=RichC;177227]..not meaning to hijack thread but I've got similar questions.
Can you elaborate more on the acrylic coat please David? Is this something thats mixed into the stucco or is it a 'paint on' product that goes onto the render.
There are probably lots of ways to do it. You could add something to make the final stucco layer waterproof, use an acrylic render/stucco layer or as I do a cement render/stucco layer with an acrylic waterproof layer painted over it. I use an elastomeric acrylic which is just a fancy mane for an acrylic that's really flexible. Hence my reference to bathroom sealers that go under the tiling.