Insulation questions

[CapePizza]

A few questions as I plan for my build.

1). I had seen a post where the builder used a layer of Foamglas and then a layer of the 2 inch thick FB board on top of the Foamglas (to achieve more insulation). Is there and advantage to this as opposed to using 2 layers of the FB board? Or is just the 1 layer of FB board sufficient?

2). Would the layer of Foamglas support the weight? Would 2 layers of FB board support the weight of the oven?

3). I've seen the soldier course placed on top of the floor bricks and also alongside, butting up to, the floor bricks. Is one way better than the other?

4). The insulating blanket. Is 3 inches the recommended thickness? I suppose more is better, but will 3 inches be sufficient? I'm limited on my hearth size so if I can stick with the 3 inches that would be best.

Thank you for the help.
John

[UtahBeehiver]

1. FoamGlas is hyrophobic - won't absorb water, hence usage. Min. 2" CaSi or AlSi or 4" p/vcrete 5 to 1. But you can mitigate
2. FG has sufficient compressive strength as well as CaSi.
3.Either/or but soldiers must "not" sit on concrete hearth. Particular reason for soldiers? Full height soldiers not recommended due to outward forces at dome and soldier joint and may require buttressing. Consider half header.
4. 3" is good as long as it is ceramic blanket.

The search option will can lead you to many of these answers

[CapePizza]

Thanks very much for your help, UtahBeehiver. I've been meaning to ask you, regarding your "screen name". Do you keep hives/honeybees. I do which is why I ask :-)

[UtahBeehiver]

Nah, it is the State of Utah symbol. Although I did let a neighbor use a vacant portion of out lot to place his hives and he would give me some raw honey here and there but the novelty wore off and he gave the hives to somebody.

[CapePizza]

Well.... bee keeping is a challenge. But, when you get honey, it's worth it. As it is to have your hive survive through the winter.
I've never seen pictures of your oven but today clicked on the link to your build. I was truly impressed, inspired, and really pretty amazed at the outcome. I have an arts background and I would say what you've built is a work of art (not that one needs an "arts background" to see that :-) But I really enjoyed seeing what you built. Glad I found the link. The copper sheet finish is pretty amazing.
I keep thinking I'm ready to start my build.... but the more I study the postings on the FB site, I realize there's quite a bit of information there and quite a lot to learn in order to do it right. It's a big project to take on
and, I guess in the end, one wouldn't want to wind up with a half assed outcome. Thanks again for your help!

[UtahBeehiver]

There is a sticky in the Newbie Section called Treasure Archives or something like that. It shows some of the more documented builds on the Forum.