? 4" calcium silicate board under the floor?

[Padraig]

Hi all,
My hearth pour is curing and I'm itching to get started next week with the floor and dome.

I love the thread in this section:

"If you had the chance to rebuild your oven, what would you change?"

Many posters say they would put more insulation under the floor. Will adding more insulation make the floor hotter, or just hot for longer? I don't want burnt pizza!!

I have excess calsil board and could double up to 4". Would you do it?

[david s]

More insulation is subject to the law of diminishing returns, as well as taking up more space. Because the stuff is expensive a relatively high cost for little gain can be the result. If you had 4” and contemplated adding 2 more, I’d say don’t bother, But if you have it you may as well use it. It will also raise your floor level.