can ceramic board be cut just for floor size

[merlyn]

I`m ready to go but I need advice on the ceramic board,, I found a supplier near me[ I live in Al.] that has the 2 inch board in 24 by 48 inch size . I can cut this to fit my interior space on a 36inch oven . How ever on all the photos, it shows this also going under the exterior wall of fire bricks. Is this necessary ??? or can I just cut the ceramic board to fit the center floor and run the fire bricks right on the concrete I have a 5.5 inch thick slab poured for a base I guess I was wondering if the fire brick would transfer enough heat to crack the slab .. I doubt that I would have a heat loss .I would appreciate any thoughts on this ..

[GianniFocaccia]

Re: can ceramic board be cut just for floor size

You must under-insulate the walls of your oven or any heat you put into them will bleed via conduction directly into the concrete below. You would be wise to extend the floor insulation 1-2" wider than the walls. If you can swing it, go with 4" of insulation. 2" is on the thin side. You won't be sorry.

[stonecutter]

Re: can ceramic board be cut just for floor size

Insulation... in your case, ceramic board insulation....is installed first over the structural slab, and the firebrick is set on top of the insulation.

If you don't have insulation under brick, heat will constantly transfer into the mass it is contacting.

So, you should also have insulation under the base course of your dome, the same as you need insulation under your floor brick. If you don't want to use ceramic board under your dome courses, use perlite/portand or vericulite/portland at a ratio range of 5-8:1 (perlite/vermiculite - portland)

Your brick floor can be cut to fit inside the diameter of the dome or you can extend it so the dome is resting on floor brick...doesn't matter which. Either way, there should be insulation under the floor brick.

[merlyn]

Re: can ceramic board be cut just for floor size

Thanks for the info . I think I will buy a 1inch 24 by 48 also and cut it so it will go under the 1st course of fire brick. I will of course double it up for the suggested 2 inchs .. can always use the xtra under the landing I guess . Looking forward to playing with the dome shape . Did a fireplace and a smoker this will be a new challenge.. Thanks again for reply..

[CV_Oven]

Re: can ceramic board be cut just for floor size

Left over board can also be used for door insulation.

[Prairie Valley Bread]

Where can I find ceramic fibre board?

Does anyone know a distributor for ceramic fibre board? Or even enough for a 36 in oven?
I live in beautiful Summerland, BC, Canada.