Using cordierite tiles overtop of firebrick floor.

[Cyrzee]

Long time listener, first time builder.

I’m working on a 40” dome oven using reclaimed bricks from my original 1940s fireplace.

Currently I’m laying out the floor and I’m not too happy with the consistency of the brick sizes. Some have small indent on the edge that are causing gaps.

My question is: can I lay 15”x12 cordeirite baking stones over top of the firebrick floor to make for a more even and clean cooking surface? I’m primarily using the oven for pizza nights.

I will level off the firebrick with a sand/clay mix, so I figure the baking tiles will sit nice and flat.

Any input is greatly appreciated.

[MarkJerling]

I can't see why you can't use baking stones, but I also can't see why you'll need to. I'd simply use a thin layer of sand under and level the bricks that way. You mention that you're using fireplace bricks: If these are ordinary red brick and not firebricks, then you'll find that they will not cope with the extreme heat in a pizza oven for long. It would be better to purchase proper firebrick for your oven.

[david s]

The performance of the cooking floor bricks is really something that you can only find out in practice. It is possible, but usually unlikely that solid house bricks will last.it has more to do with the clay composition than the temperature to which they are fired. The creamy coloured (less iron oxide) ones are more likely to be better performers, but no guarantees. Unless they are specifically manufactured firebricks, you are rolling the dice.
Regarding the levelling, any adjustments made by using a levelling medium or grinding or sanding, is only needed if the bricks are not a consistent height. In manufacture of clay bricks the clay composition, water proportion and resulting shrinkage as well as inconsistency in kiln temperature due to kiln placement, causing further inconsistent shrinkage, leads to a variation of brick height. This variation is normally compensated for by the mortar course between bricks when they are laid in the normal way. If you carefully select the bricks for size you can probably loose lay them with no levelling required.

[Petter]

Corderite has about 4 W/mK in thermal conductivity if I remember correct. It is high and the limitation will be short baking time. Expect difficulty to do sub 2 minute pies without burning bottoms. Besides that, I can't see any issues.

https://community.fornobravo.com/for...ity#post436389

[Cyrzee]

[UtahBeehiver]

You may want to consider cross bracing of the wood stand. These ovens are really heavy when completed. Although we typically do not recommend wood bases due to expansion and durability there have been a few builders using them on smaller diameter ovens. In any event we recommend cross bracing. The fireplace bricks look like they are in good shape, if you have an angle grinder with a diamond cup it you knock of the side joint tabs in short order and allow better spacing of the floor bricks.

[deejayoh]

Taking all the time and labor to build a large oven, I don't know that it makes sense to cut corners on the floor tiles. It's maybe 30 bricks? Call it $100? I'd use bricks, as having a floor that retains heat is one of the keys to good crust. You want the leoparding!

[Cyrzee]

Here’s what I’m thinking. These 7.5” cordierite tiles are about 3/8” thick.

[MarkJerling]

It looks like an interesting experiment but not one I'd be willing to try myself. I look forward to seeing if it works for you or not.

[deejayoh]

Here’s what I’m thinking. These 7.5” cordierite tiles are about 3/8” thick.

Sounds like cordierite will handle the heat, but a tile that thin is not going to retain it. You'll have to recharge them much more often

[david s]

It looks like an interesting experiment but not one I'd be willing to try myself. I look forward to seeing if it works for you or not.

I agree. The thinner the refractory the greater the tendency for it to fail. Looking forward to hear how they perform.