Insulation under vent area brick?

[Greg in RI]

Hi there,

I'm using 2" thick FB board insulation under the fire brick floor of my oven. I'd like to lay a slab of 2" thick blue stone abutting my insulation for my stove mantel but it would also lie under a portion of the fire brick that will lay in the vent area. Are there any drawbacks to NOT insulating under all of the vent? I would build my vent area (including brick floor) and enclosure on top of the blue stone. The blue stone will be a slab 18" by 72", cantilever slightly over the front edge and sides of my base and be used mostly for counter space when the stove is complete.

Any thoughts?

Thanks. A beautiful day here in RI to work on the thing. With days like this I'll be able to work through the winter!

Greg in RI

[GianniFocaccia]

Greg,
An uninsulated bluestone entryway floor will bleed residual dome heat via conduction through direct contact with your oven floor and entryway walls. See SCChris' thread on his direct-connect soapstone entryway heat loss. If you have a thermal break between your dome and entryway (including entryway floor) then no problem.
John

[Greg in RI]

Hi John,

Thanks for the information. I did read the thread started by SCChris on soapstone. Interesting. I don't think I'm ready to use soapstone as my WFO floor but it is an interesting thought. It sounds like you're the expert in this application.

My bluestone idea would place the bluestone under the fire brick of the vent floor, in place of insulation. Actually, as I lay it out, 1/2 of the vent floor would have insulation under it (the part closest to the stove) and the outer half would have blue stone under it. I am concerned about the thermal loss through the stone versus having insulation under the fire brick but I'm not sure it would be significant enough to bleed heat out of the WFO dome/floor. Your thought on the stop/space may be what I do.

If I use a solid piece of bluestone under a portion of the vent area fire brick floor, it eliminates the need to cut/notch the blue stone to fit around the vent opening.

Again, thanks for the lead on the thread.

Greg