Oven floor

[Sezofala]

Hoping to make pizzas in Amsterdam soon.

Instead of firebricks for the floor I want to use square tiles/slabs of the same material so I do not have to cut the bricks to the round dome shape and save on renting an expensive bricksaw. Costwise and timewise. Its not much more expensive and also less seams for the peel to chip. The dome will then be placed on top.

is there a prohibitive loss of heat as this floor will be square shaped and will stick out under the dome? Or any other problem for that matter?

Thanks.

p.

[SableSprings]

Welcome to the forum Sezofala!

I'm assuming you are thinking of casting the oven dome since you don't want to rent a wet saw to cut bricks. (Lots of well documented cast builds here and David S is one of our casting experts.) You need to make sure the top slab is well supported (even cast domes can be heavy). In general, the insulation below your cooking floor is the most important way to stop heat from "leaking" out from the bottom. It really doesn't matter if your cooking floor sits inside the dome or if the dome sits on top of the cooking floor. The point raised by many who favor the inside dome approach is keeping the ability to replace a damaged brick or tile on the floor. However, you will find that it is very rare to have to replace a cooking floor brick/tile during normal use. My brick dome was built on top of the cooking floor and I've put 6,280 pounds (2,848 KG) of dough through my oven since it was completed in 2009 (mostly bread - 5,456 loaves/baguettes). To date, I have no portion of the cooking floor that shows need of repair/replacement.

Since the dome and floor will expand/contract with each firing, you do not need to mortar the cooking tiles in place nor the dome to the floor. The recommendation here, is to leave 2-4 mm gap between cooking floor and the dome if setting the floor inside the dome. Since you are planning to set the dome on top, that's not an issue...your dome will move back and forth slightly on top of the outer cooking floor. The cooking tiles are usually leveled with a damp mixture of clay and sand. Gaps between each unit will be filled with ash after a few firings.

You do want to make sure that your entire cooking floor and dome are well insulated from your supporting slab and the outside elements. You can use a brick chisel to cut floor tiles that extend more than 2-3 cm beyond your dome perimeter. Those ragged edges will be covered with the outer insulation (ceramic batting or insulating concrete) and then hidden further by your outer enclosure (stucco, cement, building, etc.) The biggest issue with insulation is that most kinds will readily absorb water and so you need to make sure you plan for that. We recommend weep holes in the supporting slab and separating the bottom insulation board from the slab with either scrap sheets of tile or some other waterproofing layer.

Sorry to be so wordy...but now is the time to make sure all of these WFO building principles are mentioned. I hope this answers your question and either confirms what you know or gave you some additional thoughts on your build.

[david s]

Hoping to make pizzas in Amsterdam soon.

Instead of firebricks for the floor I want to use square tiles/slabs of the same material so I do not have to cut the bricks to the round dome shape and save on renting an expensive bricksaw. Costwise and timewise. Its not much more expensive and also less seams for the peel to chip. The dome will then be placed on top.

is there a prohibitive loss of heat as this floor will be square shaped and will stick out under the dome? Or any other problem for that matter?

Thanks.

p.

A large angle grinder fitted with a tile cutting diamond blade will easily take off the corners of the bricks or tiles that stick out. You can be pretty rough as they’ll be covered up. A small angle grinder works but you’ll have less depth of cut. The larger the floor tiles are the more likely they are to crack because of uneven heating and thermal expansion. Floor bricks or tiles are best laid loose to allow for this expansion and possible replacement if required.