Building oven whilst Coronavirus in NYC

[NYFirinci]

Sorry for separate posts, Let me also mention that the clay bricks are on top of the concrete, not insulation.

[Chach]

It seems to me that you insulate the oven floor then put a ton of thermo mass on top of it such as concrete then refractory concrete then concrete blocks then fire brick. I know it sucks but if it were me at this time I would for sure deconstruct as JRPizza suggested and start with a new insulating layer that would support the weight of the oven walls. IMO if this did work out for you I believe you would need a lot of fuel to heat that floor up. These builds take a lot of time, money, and commitment but in the end it will last a life time if built with materials intended for their specific applications. What I am saying don't use a butter knife for a standard screw driver. The same goes for building materials even though rockwool can withstand the heat doesn't make it the ideal choice for the insulating layer for your oven walls and floor. Hope this helps.

Ricky

[NYFirinci]

Chach Thank you for the tip. The walls are not standing on the rockwool insulation. Do you recommend me adding a ceramic fiber blanket insulation or a ceramic fiber board? And what should I put on top of that before laying the fire bricks? Sorry for all the back and forth, I want to do this right and not make anymore mistakes. Thank you again everyone!

[NYFirinci]

Also, could you please mention how many inches each layer should be. Thank you

[Chach]

2" minimum of the fiber board some elevate it off the slab using ceramic tiles and they also drill a few weep holes in the slab so if water enters it can exit underneath the oven. Other have used a product called foamglas which doesnt absorb water instead of the tile and put the fiber board on top of that. this is what I did. I also did 3" of blanket over the dome after it was built. I believe 2" is sufficient for that. So it goes fiber board then make a paste of 50% fire clay and 50% sand notxh trowel that like setting tile and put your fire brick floor right on top of that.

Ricky

[NYFirinci]

Chach thank you again Ricky!! This definitely clears
My mind and I will work on this this weekend. Another question, is 1.5 inch fire brick for the cooking floor enough or should I go with the 2.5inch thick firebrick?

[Chach]

I went with a standard fire brick which was 2 1/4" and I am very happy with that.

[NYFirinci]

Sounds good, I’m doing my research on where to buy all my supplies since private establishments are only working with large commercial orders. Thank you again for all the advice and time you put in.

[JRPizza]

I am not sure you caught this or not but we have been talking about both the floor and walls of the oven sitting on insulation. The ideal oven has the correct amount of thermal mass (walls and floor) insulated from the surroundings (concrete hearth and air) so that once you heat the thermal mass it will slowly release heat to the interior of the oven as it loses heat cooking your food. Any other way to build the oven is a compromise in heat retention. I have no idea how much less efficient the oven will be with the walls bleeding heat down into the concrete base but I'd hate to do all the work building an oven that did not perform as well as it could. If you have an unlimited supply of wood to burn and time to fire the oven maybe it is not as big of a deal.

[NYFirinci]

JRPizza Yeah, I’m still trying to figure out how else I could insulate under the wall, but it will be a lot of work. I don’t think I could cut off the whole 4 layers to put insulation underneath the walls. I might just rely on fueling it up with excessive wood. Thank you for all the tips