Vermicrete over insulation blanket

[tony007]

I hope I'm posting this in the right place. I'm really new at this.

First I want to thank all the contributors to this forum for the great information, it provided the guidance and inspiration I needed to get this far in my project. Also, many thanks to the folks that provided supplier information in Florida.

I have completed the dome and I'm at the point of insulating it, my question is - will the Vermiculite/cement mixture on top of Insulation blanket (Superwool) and chicken wire compress the insulation and reduce the insulating properties.

I'm considering the following and would like your comments:
> Should I use a layer of aluminum foil between insulation and vermicrete?
> Instead of chick wire should I use stucco lath which will provide more holding/binding for the vermicrete and not compress blanket much.

Cheers

[tony007]

Re: Vermicrete over insulation blanket

I received my answer under the insulation efficiency thread.
>Aluminum foil is a bad idea.
I'm still thinking of the stucco lath approach, at may not rust like chicken wire.

[dmun]

Re: Vermicrete over insulation blanket

The insulating blanket is pretty dense stuff, and the vermiculite concrete is lightweight. It won't compress the blanket. There's no need for a metal layer between the two at all. This has been done hundreds of times, no need to reinvent the wheel.

You may find it useful to put a circle of something around the dome to contain your more vertical layers of vermiculite concrete as you start to lay it up. This would be a good use for your expanded metal lath if you've already bought it, otherwise anything that will bend will do the job.

[Neil2]

Re: Vermicrete over insulation blanket

I put the vermacrete (4 inches, 10:1 mix) directly onto the brick dome. No blanket.

[nissanneill]

Re: Vermicrete over insulation blanket

Tony,
so long as you don't compress the blanket (as Dmun said it is pretty dense and would prove difficult to compress) the layers of vermiculite cement will not affect the insulative properties at all.
Even with the chicken wire form over your bricks, it is faily difficult to get the first layer to hold together and stay in place.
I put a small portion of fireclay in mine which made the mix much stickier and easier to plaster over the wire. I also started at the top and worked my way down, not easy but for me proved easier than from the bottom up, (as my oven especially thr insulation was up against a retaining fence wall and access confined).

Neill