Oven floor insulation

[Drgolf369]

My oven was built by a mason. The floor is fire birck over 3" mortar slab over corrugated metal. I want to insulate the undersurface which is the ceiling of a closed wood storage area. Any suggestions?
Joel

[jeeppiper]

Re: Oven floor insulation

I dont think that really is going to do much for you. You want to isolate the firebrick from the slab so that the slab doesn't absorb the heat from your firebrick.

[Drgolf369]

Re: Oven floor insulation

Jeepiper
Thanks for the reply.
I can't do that since the oven is finished. Won't the slab store and release heat?
I have noticed that when I heat the oven to 900-+ I have to let the floor cool to 750+- Or the bottom of the pizza will burn.
If I put 8 loaves of bread in at less than 650 the oven temp drops quickly and I don't get the "burn" that provides that special flavor.
What are your experience?

[Tscarborough]

Re: Oven floor insulation

Don't hire a mason to build an oven, hire an oven builder. You are pretty much SOL without a rebuild, but all is not lost, just accept it for what it is and learn to maximize what you have.

[Drgolf369]

Re: Oven floor insulation

Thanks,
As my experience increases, my results become more consistent.

[Tscarborough]

Re: Oven floor insulation

If you haven't already, buy an IR thermometer and learn the characteristics of your oven. After a while you won't need it, so buy a cheap one.

[Drgolf369]

Re: Oven floor insulation

I have one and have had this oven for 2 years. I only seem to learn from my mistakes. It it works by luck, I don't know what is right.

[Tscarborough]

Re: Oven floor insulation

If my oven had no floor insulation, I would build the fire on a grate and keep the ashes cleaned from the floor during heatup.

[Drgolf369]

Re: Oven floor insulation

I think I am going to buy ceramic board and instal about 6" under the floor. That should be enough.

[Tscarborough]

Re: Oven floor insulation

Under the concrete slab is wasting money. If you can raise the firebrick and install a couple of inches BETWEEN the hearth and slab you are golden.

[Drgolf369]

Re: Oven floor insulation

That would be almost a rebuild and the oven is function well.

[Tscarborough]

Re: Oven floor insulation

Right, so insulating the slab is a waste of time and money.

[cobblerdave]

Re: Oven floor insulation

Gudday
Insulating the hearth and thereby raising its height will change the ratio between the door height and the height at the top of the oven. Many books quote a definitive measurement of the door height to be 63 per cent of internal height of the oven. This proportion has its origins in a book " bread ovens of Quebec" were this was an average of measurements of many ovens were the door height to oven height could vary from 44 per cent to 87 per cent.
So if insulating changes the magic 63 ratio I would not panic as long as it is close to 2/3 of oven height . Yes I have a mate who has a barrel oven with an internal chimney and a door height to oven internal height of ( trust my memory here) about 50 per cent. Yes he flashes it up with the chimney open but after the fire takes well, he caps it off and the oven works better and uses less wood and time till heat up than it does with the chimney uncapped.

Regards Dave
The bread ovens of Quebec, National Museums of Canada , Ottawa . Lise Boily & Jean-Francois Blanchette 1979