Assembling Cal Sil insulation

[Rivernook]

Hi to everyone.

My question is do I need to bond together the Cal Sil insulating sheets under my oven floor, or just place them flush against beach other? The boards are 1000 mm x 610 mm, so there will be some seams under the floor.

I will be pouring a 4" vermiculite hearth, plus the 2" insulating boards on top. My oven floor will consist of 12" x12" x 2" refractory tiles. My understanding is the Calsil can sit directly on the vermiculite, and the oven floor can sit directly on the Calsil.

I have also been reading many discussions regarding more or less thermal mass in the oven floor, heat up times, loss of floor heat etc.
With the help of some sound contributions to the forum, I have concluded:

Because I will have both Vermiculite and Cal Sil insulation, I should not lose too much heat from the slightly thinner 2" floor, and I should also get the floor temp up quicker. Also there will be less seams, therefore less gaps for heat loss? Does this make sense??

All the best

[biondoli]

You are correct with that insulation you are more than fine at the bottom...I put only 2" boards on top of the heart.
I would not worry about the joints, if you need just level the boards with some fire clay.

[Rivernook]

Thanks very much. I will post some photos soon on my progress to date - next to do is put the floor down and start building!

All the best

[dmun]

Just as a side note, yesterday I had a very hot fire in my oven, burning some scrap lumber. After dinner I noted that my landing, which is a bracket supported piece of two inch slate was very hot to the touch, as well as the arch over the opening, but the slab under the oven floor was still cool to the touch.

This is with 2.5 inch insblock19, which is not supposed to be as good an insulator as cal-sil.