securing insulation before hearth building

[chickade]

I have picked up my Foamglas 2.5 inch insulation. I found it to be a bit more fragile than I anticipated, so I am planning to place 2 inch thick cal-sil board over it and the bricks of the hearth on top.

Would it be wise to use some kind of fireproof insulating tape or cement between the concrete slab, Foamglas, calsilboard layers?

Will the weight of the oven and the housing be sufficient to keep everything in place?

Thanks, Sarah

[david s]

Re: securing insulation before hearth building

IMO the weight alone is sufficient to hold it, i don't use anything else, but you could use refractory cement if you want.

[Les]

Re: securing insulation before hearth building

Just go with the weight - the board's not going anywhere.

[UtahBeehiver]

Re: securing insulation before hearth building

Chickade,

I used the same set up as you, 2" FoamGlas and 1 1/2" of CaSi, the weight of the dome is plenty sufficient. One thing you may want to do, the FoamGlas is like you say fragile, make of a batch of home brew and do a render coat on the FoamGlas and CaSi. This will protect the boards from damage from you toes as you build you dome.

[chickade]

Re: securing insulation before hearth building

Could you give a brief description of "render coating"? Also a definition of "home brew"?
Sarah

[chickade]

Re: securing insulation before hearth building

I did research and found that "home brew" refers to a refractory mixture and "rendering" means to use a stucco based product for a finished surface. How am I doing? Thanks again. Sarah

[UtahBeehiver]

Re: securing insulation before hearth building

Either works but if you use homebrew for your dome, you will have all the materials to slather on the outside of the FoamGlas/CaSi. Or as you build you dome, you will have leftovers too, use it then and not waste. Good luck.