Aluminium layer

[Luke.Brod]

Hi Guys.

I have insulated my oven and done a layer of Perlite render and done a red brick external dome.

The supplier recommend a aluminium foil layer inbetween insulation ceramic blanket and render to stop blanket sucking the moisture out of the render, this I have done.

So it goes oven, blanket ,aluminium foil, Perlite render then red brick.

My worry is now I'm doing my curing fires at the end of the day if I put my hand in the oven it feels humid. is the moisture struggling to evaporate because of the foil! Am I screwed? Or will it just take longer to cure?

Thanks

[Luke.Brod]

I'll just add that I haven't finished my brickwork yet so it isn't a massive job to cut the top of the perlite, 10" square, then remove that bit of foil. Providing a passage for the moisture to escape. Then render.

Or I could just wait until I complete the curing fires and if it does dry out complete brickwork. Or will this cause problems in the future if moisture does get in.

The oven is under cover but the back side will get wet due to driving rain.

[david s]

You can probably make a thin spiked tool to poke through the perlite layer and perforate the foil, provided the perlcrete is a lean brew and not too thick. The issue of the perlcrete sucking the moisture from the outer render is precisely the reason I applied it too. So now after applying the outer render layer I wrap the whole oven in cling wrap to hold the moisture in the outer layer for a week. As you've already done nearly all the outer brickwork it would probably be best to drive off as much water as you can by the drying fires before finishing the brick top. Try to keep it covered if it looks like raining.

[Luke.Brod]

Thanks David,

I agree with your comments, I've just cut a 10" x 12" cap off the perlcrete and cut the foil off that area.

Im going to run fires all day. Then tomorrow seal the cap back on leave for a day or two. Then start fires again. There was a bit of moisture on the top of the ceramic blanke, in the form of droplets, but not too much, better safe than sorry though.

I'm hoping that any moisture in the walls will rise because there is nothing I can do about that now.

Hope this is enough.

[david s]

I'm not sure if you read my post her about my experience using aluminium foil and why I don'y use a foil layer.
https://community.fornobravo.com/for...573#post439573
You can usually feel the moisture which makes your hand clammy or if still unsure you can throw a sheet of plastic over the oven to see if moisture is condensing under it.

[Luke.Brod]

I've just read it. Wish I'd seen it before.

I regret using the foil now.

There is definitely moisture coming out now. I can see, with todays fires, droplets and sometimes a little steam coming out of the top where I have cut it away.

I live in the UK so I get a lot of rain, however the oven is under cover. But the back will get wet when the rain drives across the field behind it.

Do you think that the moisture in the walls will make its way to the top and Escape through the 10"×12" gap in foil that I have created?

[david s]

If you see steam you are going at it too hard. Back off or you’ll risk damage. Both the partial outer walls and the foil will both hinder the drying process so in your case it will just take longer. The moisture will find its way out. Just keep it slow and have patience.