ceramic floor board amount

[Eastside3]

Im putting together a Premio 2G110. I want to do everything I possibly can to limit the heat build up in the storage under the hearth slab. I have a large base with two compartments. One os for wood storage while the other ive run conduit into in the event I want to use the storage for something else down the road. I want to keep my options open. Whether I put a small fridge in there, use it for storage, or come up with some other idea, I want to do everything I can to lessen the heat build up that permeates the floor. Im pouring the hearth slab and it will be 5 inches thick. I know 3 1/2 - 4 inches is standard. On one thread I read, where someone asked "What would you differently if you could do it all over?" the most common answer was that others would opt for more insulation. Its for that reason that I built my base a little bigger, so that I can add more insulation around the dome, while still allowing for the air gap between the dome and the wall structure. As for the base, I was considering adding a piece of calcium silicate board underneath the insulation that the kit provides. The kit itself comes with 3 inches of ceramic floor insulation. Ive never worked with this ceramic insulation material and I dont know whether it will compress under the weight of this oven. The oven is obviously heavy but it is an even weight distribution, laying flat. Again, my goal is to lessen the heat transfer and the build up under the hearth slab, and I thought adding another insulation layer would be good. Any thought, concerns, issues? Vermiculite is more old school from what I hear, so for those who might suggest to just pour a vermiculate layer on the concrete slab, this seemed to be the standard practice prior to using ceramic insulation. Todays ceramic insulation boards seem superior in terms of insulation properties, but again, I wanted to get feedback from the board here. Thanks all.

[cobblerdave]

Re: ceramic floor board amount

G'day
The standard level of insulation is 2 in of ceramic fibre or 4 in of pearl/Crete. Having roughly the same insulation value.
Adding more is never a bad thing.
Pearl/Crete is cheaper and more available but has the disadvantage of a longer wait in good weather conditions to dry before placing the oven on it.
Both will more than handle the weight of an oven because even though the oven is heavy its weight is over a wide footprint.
Even with the 3 in of insulation supplied you find the underside of that slab will never get to more than a few degrees above ambient even over a few days. Yes the insulation so that good.

Hope this helps.
Regards dave

[Eastside3]

Re: ceramic floor board amount

Dave, you telling me that the insulation is "That good" is something im hoping is true. One of my fist posts was, and still is, a question about whether to use a floating slab or not. The alan Scott design for making a bread baking oven calls for a floating slab that has the rebar sticking out of the slab and siting atop the Concrete block base. His design reason was to create a heat break. All the concerns over having the concrete slab expand and ruin the surrounding structure ALL comes into play when the heat is hot enough to become an issue. So if using extra insulation can mitigate the heat transfer even more then it stands to reason that its good to just buy another sheet of the ceramic insulation. Heck, ill ad 2 more sheets for a total of 5" if people tell me this is ideal? Im not as worried about the cost of the sheets as I am over the cost of repairing what breaks later.

[Tscarborough]

Re: ceramic floor board amount

The Alan Scott design is outdated and technically incorrect. If it disappeared from the internet the world would be a better place.

[oasiscdm]

Re: ceramic floor board amount

Hey TB you're on fire. Lol.
I looked at that one and thought nahhhhhhhh it makes no sense

[Eastside3]

Re: ceramic floor board amount

TB Im glad to hear im not the only one who found some issues with that design. When my Mason started talking about how he built "1" oven, yes one, uno, three minus two, it gave me a moment of pause to think that perhaps his advice would be worthy of having a few grains of salt to go with it. Who knows, he my be a master mason and know every secret handshake, but its what he said next that gave me a raised eyebrow. ... "Yeah after we were done building the dome we then filled the entire cavity with a mixture of portland cement and vermiculite, with just enough water to get it to clump but without compacting it." There were no layers of fire blanket in his build. It was old school. Im not one who is afraid to overbuild, hell I LEAN towards it, but the amount of concerns brought up about heat breaks and concrete expanding and how the walls will crack and the rock vaneer wight fail because of the concrete expansion.His concerns were noted, I understood them, but I never read anyone talking about their failed concrete base or their expanding walls. FB has a pretty extensive group of people following them, contributing to this forum, and Ive not run across people saying that their oven (when built to spec) had issues to the degree my mason warned me of. I suspect he isnt familiar with some of the kiln material and ceramic fire insulation boards, and perhaps he was thinking I was simply going to lay tile directly on a concrete slab. But frankly Im thinking that IF the insulated boards werent sufficient then there would be alot of people complaining. My second thought is that I simply need to find that magic point where more insulation becomes a problem. If I added two more inches (5 total) i would love to have close to zero heat in the storage below. Again, my base has two storage compartments. The one in front is exposed and will be for wood. The one on the side will have a door and could hold a fridge or possibly house some electronics for various yard ideas I have. Hell I could use it to age cheese or make beer in winter..... semi joking. The point is, the more I can keep heat getting to it, the more options I will have with how I can use the space. Im not about to put any electronic components in it if it runs hot.

[Eastside3]

Re: ceramic floor board amount

Colin, I just saw your list of pictures from your build. Im just now going through them. Take to heart the fact that your build out is serving me well in looking at the steps you took along the way. Im glad you put this together. I too plan to catalog all my steps and pictures.

[GianniFocaccia]

Re: ceramic floor board amount

You can't go wrong 'borrowing' all you can from Colin's build. It's definitely a first-rate oven.

FWIW, my oven floor insulation is 2" of CF board sitting on 3.5" of vermicrete. The bottom of my 4"-thick support slab barely gets warm to the touch after a long pizza session.

Best of luck with your build. If you get the opportunity to draw up oven plans prior to cutting a single brick, I'd highly suggest doing so. You will be able to work out dimensions and construction questions beforehand and save yourself a ton of time and aggravation should you have to go back and remedy something that didn't come out the way you wanted it to.

John

[cobblerdave]

Re: ceramic floor board amount

G'day
Took a min to look at the specs of the primo 2G110.
That's a seriously good piece of kit. 3 in dome thickness, 2 in floor , 4 ins of ceramic blanket on the dome and 3 ins of ceramic board.
Recon there not wrong to claim it of restaurant standard .
Regards dave

[UtahBeehiver]

Re: ceramic floor board amount

You won't go wrong by adding additional floor insulation Whether it be CaSi board, FoamGlas, Pcrete or Vcrete or Insulating Bricks, your choice, your budget.

[Laurentius]

Re: ceramic floor board amount

Hi Eastside 3,

If you can go with 5" of ceramic fiber board at no economical hardship, then that would be the route to take.