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Xabia Jim 02-22-2008 11:41 PM

Adding Hearth Insulation
I found that my hearth could use additional insulation. ....something that may be difficult after installation.

I was able to use clay building tiles (flat ones) to put a shelf under my hearth and then stuff insulation into that opening, This gave me an extra 6 inches or so of insulation and me thinks it makes a big diference keeping the hearth hot.

So, fyi it can be done.

arevalo53anos 02-23-2008 06:32 AM

Re: Adding Hearth Insulation

A simples layer of 2+ inches of vermiculite/cement or, even better, a couple of sheets of ceramic blankets will do the work without the need of the tiles.
Both the blanket and the vermiculite can be maintained in place just using a thin wooden table (higher temperatures over there will be below the 50șC)


gjbingham 02-23-2008 07:29 AM

Re: Adding Hearth Insulation
Do you have any pics of that fix? I think I understand, maybe. I've got to check under my hearth slab next time I cook. I'm still not happy with the way the floor of the oven is retaining heat.

CanuckJim 02-23-2008 08:29 AM

Re: Adding Hearth Insulation

On my to do list in warmer weather is to attach SuperIsol panels underneath my oven. Glue won't hold them there, so I'm thinking a few pieces of steel studding and tapcons will work.


Xabia Jim 02-23-2008 08:39 AM

Re: Adding Hearth Insulation
George I don't have any useful pictures. Basically the tiles formed a shelf in the opening under my oven, then I rammed in insulation so it packed tightly. Cemented in the front and that completed the fix.

The tile shelf still get's warm which tells me that the insulation layer is holding more heat and the hearth should be warmer and hold it longer.

Xabia Jim 02-23-2008 08:41 AM

Re: Adding Hearth Insulation
And, I'd definately agree that putting a high tech material under there and holding it in place somehow would probably be more efficient. I think I did my fix for less than $10 though. (my labor is free)

gjbingham 02-23-2008 11:24 AM

Re: Adding Hearth Insulation
You work for wine - not free, unless you make it yourself.

Thanks for the explaination. I'll check mine tomorrow when I fire the oven up again.

gjbingham 02-23-2008 11:29 AM

Re: Adding Hearth Insulation
BTW, I'm starting to think that 6 inches of vermiculite under the dome is probably a better number to shoot for, huh? It seems to me that if you're loosing heat into the hearth, you're basically trying to heat the entire hearth slab. Would insulation under the slab help the situation?

Frances 02-23-2008 11:36 AM

Re: Adding Hearth Insulation
Good question George, that's what I was wondering, too.

On a similar quest I was wondering whether adding another layer of bricks to the bottom of the oven might be worth trying. My baking is going well, but it does strike me that it could be better with more floor heat. Any advice for this??

gjbingham 02-23-2008 05:07 PM

Re: Adding Hearth Insulation
Bricks underneath would certainly increase the mass, and might make you use more firewood to get the oven hot if your insulation is a bit thin. Good question! Whether or not it will prolong the heat of the oven....I guess it's conceivable. My gut is still telling me that without sufficient insulation under the oven floor, you're basically trying to heat the entire hearth slab, which is going to continue to suck heat away from the oven floor.

Frances, have you felt under your hearth for warmth?

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