6" insulation under dome?

[jimkramer]

I wanted at least 4" of cal sil under the dome, and got two boxes in 1.5" thick boards. Any reason to go over 4.5"? I have enough boards for 6", but I'm concerned about settling under the dome with that much (I think Lee encountered that) and suspect there's a law of diminishing returns after 4.5" of insulation under the dome. Any point to 6"?

[Dino69]

Re: 6" insulation under dome?

I am about to close my dome and have four inches of cal sil under my floor. It seems like a lot but I wanted to make it as well insulated as I could. Plus I got the skamol board fairly cheap and sorta close to my home.

I don't think you would have settling or any compression of the board. It is pretty strong stuff compression wise. I am not sure if you would need more than four and a half inches. I am using my left over board to make an insulated door or two.

Good luck with the build.

David

[mrchipster]

Re: 6" insulation under dome?

I wanted at least 4" of cal sil under the dome, and got two boxes in 1.5" thick boards. Any reason to go over 4.5"? I have enough boards for 6", but I'm concerned about settling under the dome with that much (I think Lee encountered that) and suspect there's a law of diminishing returns after 4.5" of insulation under the dome. Any point to 6"?

I have 2.5 vermicrete and 2 FB board and I still see a small rise in temp through the floor after a long burn, We had an afternoon neighborhood party where I kept the oven at over 800 for 5-6 hours, the wood storage bin ceiling got to about 130 at hour 5 with an ambient temp of 80 so there is some heat being lost via the floor. I did not take regular measurements.. I guess I could have added more vermicrete....

Chip