What primer to use under cement lime render

[Mogwai101]

I am installing a wood burner and the space is narrow so opted for a wet treatment of the brick/blocks revealed when taking the fire out.
I have put a render scratch coat on (about 3weeks ago) (about 1.8m2) and now need to finish it. I plan to use a cement lime sand render (1-1-6) as a top coat. I can not find advice on how to proceed- should I prime or not or wet the surface and apply the render...or what?
Looks like PVA is out but I can not find info on the compatibility of SBR products with renders with lime. Or should the scratch coat pull some of the moisture from the top coat to aid bonding?
Advice would be well received.
Tks in advance.
Christopher

 

[bobski]

For a 1/1/6 top - depending on the suction of your base, 100% make sure it's not dusty or crumbly, I'd lightly dampen - but not go on when base is wet.


Little bit of moisture there (possibly darkish) but not wet.

 

[Monkey Boy]

Water

 

[malc]

You are wasting your time with render. It will crack and fail under the heat from a log burner. You need Vitcis heat resistant plaster and that is Not diy project .

 

[Mogwai101]

For a 1/1/6 top - depending on the suction of your base, 100% make sure it's not dusty or crumbly, I'd lightly dampen - but not go on when base is wet.


Little bit of moisture there (possibly darkish) but not wet.

Thanks for the response. I have only just found the responses. My computer was displaying a message saying "waiting approval for posting"....when in fact it was posted. This what I thought would be the appropriate treatment.

 

[Mogwai101]

Water

Thanks for the response. I have only just found the responses. My computer was displaying a message saying "waiting approval for posting"....when in fact it was posted. This what I thought would be the appropriate treatment. I will post some pics when it is done.

 

[Mogwai101]

You are wasting your time with render. It will crack and fail under the heat from a log burner. You need Vitcis heat resistant plaster and that is Not diy project .

Thanks for the reply. I am hoping that the lime content will allow the render to be a little flexible and "self healing". Some cracking will be tolerable provided it does not spall of the base coat. A few coats of emulsion will cover/fill the cracks. Once the job is done will posts some pics and see what happens after the fire is lit up.
Thanks for sharing your thoughts.