Exterior wall tanking question...

[mangina]

First time post to ask all you experts on here-thanks in advance for any assistance you can provide.

I have built a pizza oven (imagine an igloo shape) which I intend to tile with a glass mosaic type of tile which will need to be frost proof but not heat proof as I have loads of insulation in the form of ceramic fibre blanket topped with a vermicrete layer.

I need the whole vermicrete layer to be fully waterproof prior to tiling as my tiling skills (almost non existent) will definitely not stretch to anything acrylic.

I was initially thinking of an sbr slurry over the vermicrete layer, then perhaps a render with more sbr additive prior to tiling.

Does this sound like it would be fully waterproof? I’ve been doing some searches and found a product called arcacem s2 to waterproof substrate under tiling. Would this be better than what I’ve described above re sbr etc

 

[Dumbo]

I would imagine @ISOMAT UK will have something suitable for this . They have something for most problems

 

[hmtiling]

Isomat aquamat elastic might be the one @ISOMAT UK ?

 

[Waluigi]

I had no idea you had to tank pizza ovens.

I’ve seen a few builds and no mention of tanking.

 

[LM]

I reckon whatever moisture that doesn’t run off that shape of building won’t penetrate too far and would quickly dry out once the oven lit.

 

[mangina]

Will definitely contact isomat so thanks for that.

Do you have to tank pizza ovens? Depends really. If you just have a brick dome, then possibly not, however there are many benefits to effectively insulating the oven (allows cooking time to extend to maybe 24-36hrs).

This insulation goes both beneath the brick oven floor and outside the dome (of which I have ceramic fibre board for underfloor, ceramic fibre blanket and vermicrete over the dome). It’s this insulation which you really need to keep dry otherwise any moisture build up here could ultimately create steam once the oven is fully up to temp (500 deg C is easily attainable). The steam could then force a big crack in any top render coat.

All of this is theoretical only. As this is my first oven a belt and braces approach is my preferred option

 

[Waluigi]

I have a couple of portable pizza ovens. Yes, the insulation makes a huge amount of difference. I just honestly didn’t realise they needed waterproofing

Not sure if it’s been mentioned but has anyone said anything about a plasticiser ?

 

[mangina]

No nothing said about a plasticiser so far. What are your thoughts on this?

 

[Waluigi]

I would speak to the manufacturer or contact other manufacturers with similar ovens.

I honestly don’t know enough about it but as I said earlier I’ve seen a few pizza oven builds but never seen them being tanked with a layer of tanking

 

[mangina]

Appreciate your help so far

I think what I’m tanking is actually almost irrelevant. The important part I guess is, it’s a dome (not a wall or a floor) which is outside so needs to be frost proof. I really don’t expect any movement through heat or otherwise (a high heat firing the other day led to zero heat bleed on the outside of the vermicrete layer-I was actually very surprised as I thought it might be warm to the touch but it was stone cold).

Any other experienced recommendations for a tanking solution to go under tiling? I’m now thing my sbr slurry idea won’t help unless there is a good waterproof additive to add to a render mix. Waterproof not resistant is what I’m after, but I’m unsure if the aquamat elastic is overkill. Especially if it locks me into having to use a special tile grout and adhesive to go over the top of it ( I was hoping to just use something like a mapei cementitious adhesive/grout)

 

[hmtiling]

Off topic but is your username pertaining to Old Greg?

 

[Bond]

Lots of excellent cement based tanking systems available, my personal preference is the sovereign chemicals hey-di system, can be made more flexible with the addition of moreSBR . A call to there technical department,might be a good call to confirm suitability.

 

[mangina]

Off topic but is your username pertaining to Old Greg?

Um.. no? Is that a person?

Lots of excellent cement based tanking systems available, my personal preference is the sovereign chemicals hey-di system, can be made more flexible with the addition of moreSBR . A call to there technical department,might be a good call to confirm suitability.

Can cement based be fully waterproof and does sbr add flexibility? I thought it was more of a primer but actually , I’m not really sure what it’s main use is for! lol
Can I ask what is it you like about the hey-di system and where you previously used it? Just visited their site and that product comes under basement/cellar tanking which would be significantly warmer than my pizza oven in the uk winter months...

 

[ISOMAT UK]

Aquamat Elastic Data sheet. This would be our best option for external waterproofing.

https://isomat.co.uk/wp-content/uploads/2015/12/e-AQUAMAT-ELASTIC-1.pdf

 

[mangina]

Thanks for this. I did see it online having checked on the website. I like that it’s available in different bag sizes because I’m really not looking at a large area. A downside appears to be that I am then locked in to using isomat adhesive and grout for the tiling above the tanking (this may or may not be a downside actually depending on price of these items)
Speaking of price can you tell me what the prices of the aquamat are and where I can find them in the Hereford area?