Placing Order for Casa90 2G

[miikee]

I plan to place an order for Casa90 2G kit this week, as I'm finished with the foundation and block base for my oven. I wanted to get everyone's thoughts on a couple of things:

1. I planned to put a 4-inch concrete hearth on top of the block base. Currently, the kit comes with 2 inches of Ceramic Fiber Board, but I plan to add an additional 2 inches of fiber board and setting that on top of the concrete hearth. Is there a need to do a vermiculite/concrete mix with having the fiber board? or should I be able to just get out with concrete?
2. The kit comes with 3 inches of ceramic fiber blanket, I was thinking about adding another three inches? Is this overkill?
3. For those who have worked with these kits before, are there any gotchas that I should look out for?

[UtahBeehiver]

There is diminishing returns on over insulating. 4" of CaSi board floor insulation is right at the maximum of efficiency. Are you enclosing the oven in a structure or not will depend or if an open dome, what is the outer coating going to be.

[miikee]

We will be enclosing the oven with metal framing and stone, but planned to coat the dome with a stucco finish before enclosing.

[UtahBeehiver]

Options, you really do not need to stucco an oven in an enclosure as long as you securely fasten the ceramic blanket, As a possible cost saving measure after you install the 2" of ceramic and once the structure walls up you dry fill the inside with perlite or vermiculite (blocking the corners with old sheet rock or plastic pop bottles to reduce volume) perlite can be bought at any supplier of CMUs (it is used to insulate the cores of the block) and usually sold in 4 cu ft bags for $15 ish a bag.

[miikee]

UtahBeehiver , Thank-you for the reply.

I was also wondering if people normally lay down cement board to cover the holes in the cinder blocks which are not filled. I was not planning to fill all of them as it seems to be overkill.

[UtahBeehiver]

I just stuff the cement mix bags in the cores I did not fill. I used durorock cement board for the base form so I could leave in place after the pour and it overlapped most of the core holes. Be sure to install some weep holes in you hearth.

[Chach]

I agree empty cement bags or you can use scrab block drop them in and they will bind inside and you can put a few more pieces until it reaches the top and then put mortor on top of that to fill the the void.

[miikee]

UtahBeehiver , Thanks. Is there a post or page that could describe these weep holes you speak of? I haven't come across this yet.

[UtahBeehiver]

do a search on "weep hole" dozens of post

[miikee]

Thanks UtahBeehiver , I found a good article that describes where the holes should be drilled and how include channels to the holes with small tiles. I saw a recommendation for FoamGlas underneath the calsil/ceramic fiber board, and I found a supplier that could ship me some however; it would cost me roughly $240 because the minimum is 36sq feet + shipping.

Anyone have thoughts on this? Does this seem high?