Rendering to oven

[myke]

There are loads of threads on rendering but did a search and got no results for fibres.
I propose to mix a 4 sand 1 lime and 1 portland cement mix I will also be adding a latex based bonding agent/waterproofer and fibres (both free from a mate)

www.wickes.co.uk/Sika-No-Crack-Concrete-Admixture/p/154064


www.everbuild.co.uk/building-products/PVA-SBR-Bonding-Agents/503-SBR-Bond

Anyone tried this stuff? I believe it will be ok as after the insulation the heat will be minimum.
Also read about a vent makes sense to me so will add one to the top.

The dome may be painted or even tiled with mosiac dunno yet.

[downunderdave]

There are many different types of fibres you can add. I prefer to use 19 mm random AR (alkaline resistant) fibreglass fibres. They are easy to work with. Add around the same volume of fibres as volume of cement. Fibres are much faster than mucking around with chicken wire, but cost a bit more.Make sure your oven is dry before you do the render layer because you don't want a lot of water trapped under it, particularly if you plan on adding a waterproofer to the render mix. Also a good idea to cover the oven for a week after rendering so moisture is kept in this layer to enhance strength.

[albacore]

I added some fibres (not the easiest thing to mix in, especially without a mixer). Still got hairline cracks!
Can't do any harm tho'.
Not sure why you would need to add SBR to the mix - what are you rendering on top of?

[sparkles]

Build looks to be coming on a treat Myke. Are you rendering onto a layer of vermicrete/perlcrete? Not clear from the photos you've uploaded so far. My garage base had fibres in it and that cracked too.

[myke]

Rendering on top of ceramic insulation at least "2 which will be covered in chicken wire got the SBR free hence the question.

[sparkles]

Ah. I put a 2" layer of ceramic fibre on then 3" of vermicrete and then covered it with a lime render using the NHL 3.5 stuff which is easy to get hold of in France