compression of ceramic blanket

[mellissa]

Will ceramic blanket compress under vermiculite layer. I see people using chicken wire to hold blanket down then adding vermiculite cement layer. I am worried that the compression of vermiculite layer, then rendering layer will compress the blanket so much it will no be a good insulator?

[david s]

No the blanket is fairly firm and provided you use a lean (10:1) vermicrete brew it is light enough not to compress the blanket.

[mellissa]

Thanks I have 1 inch and was going to double or triple layer it then vermiculite mix for 2-3 inches

[UtahBeehiver]

If your budget allows, you will be happier with the heat retention if you go with more than 1" of ceramic fiber blanket plus the v or p crete.

[SableSprings]

Will ceramic blanket compress under vermiculite layer. I see people using chicken wire to hold blanket down then adding vermiculite cement layer. I am worried that the compression of vermiculite layer, then rendering layer will compress the blanket so much it will no be a good insulator?

As David S noted, the blankets won't compress appreciably with a p/v crete overcoat. If you can do 3" of ceramic batting as you indicated (and Russell noted), your oven is going to retain heat very well (assuming you put 2" of ceramic board underneath). The chicken wire wrapped over the batting is simply intended to give your vermicrete layer something to "bite and hold" as you apply it.

Don't forget to scratch the first coat of render (over the vcrete) so the final coat of render can get good adhesion with it.

Are you going to have an enclosure to protect the oven from the elements? If not, you'll want to plan a waterproofing addition or acrylic coating for the render and something to keep water from seeping into the insulation along the oven/base seam.

[mellissa]

Thanks for the render tip. Plan is it layer blanket to equal 3 inches then 2-3 inches vercrete, then render with waterproof layer then glass tiles

[Gulf]

I agree that the vcrete is structural. It won't compress the insulation. It will support just about any amount of render. It is strongest if it is applied from the bottom up and in courses. Much like the dome brick, it will spread the weight around the dome to the hearth.