FB Brand Insulation Getting Started Discuss FB Brand Insulation in the Pizza Oven Design and Installation forums; Thanks James. what are your thoughts of using a insulating refractory concrete for the base to insulate and then cover ...

[antonio cefalo]

Thanks James. what are your thoughts of using a insulating refractory concrete for the base to insulate and then cover the dome with it?

[james]

If you are looking to save cost, Perlite and vermiculite also work well and are a little less expensive.

If you are looking for professional level insulation and oven performance, the FB ceramic insulation is what they use in commercial ovens -- and it works great.

I have always thought that was the best trade-off.
James

[dmun]

what are your thoughts of using a insulating refractory concrete for the base to insulate and then cover the dome with it?

The castable refractory insulation is expensive and hard to work with. Under the dome you're much better off with the insulation boards, which give you a flat surface for laying your floor. If you're spending the money anyway, you might as well have the best.

Above the dome, it can work. I know that canukjim used one such product in one of his installations. You have to decide: If you're spending the money for professional insulation, why not get the blanket, which is easy to use?

[antonio cefalo]

thanks Dmun, for the blanket would i just wrap the oven dry? or do a thin layer of the refrax and have it adhere to that? thanks.

also how would you lay the firebricks onto the fb board? just dry, how do you get a smooth even surface? thanks

[dmun]

The blanket is thick and dense, and pretty much stays where you put it. What you do afterword depends on the kind of enclosure you're planning. I wrapped mine after the enclosure walls were higher than the dome, and then just dumped a bunch of perlite concrete around it. Obviously dome style enclosures need more attention to shape than that.

My firebricks were uniform in thickness, so when i laid them out on the insulation board the floor was dead flat. The fireclay/sand layer is just for leveling, no other purpose. When i was standing inside the oven to build the dome the bricks would shift and creak slightly, and I thought it was a problem at the time, but it's never been a problem with cooking.

[antonio cefalo]

howe about problems with the FB sagging over time, also my plan was to put the fb down, place my firebrick on top of that and then begin the walls of the oven on top of that, so it is all on top of the FB. is this the correct approach? or should i cut the the FB and fire brich so it fits on the inside of my walls?
thx

[dmun]

should i cut the the FB and fire brich so it fits on the inside of my walls?

No. Your oven should be entirely surrounded by the insulation: it's more than strong enough to withstand the weight of your oven. As to whether to cut your floor to fit inside your walls, or build your walls on top of your floor, this is builders choice.

[splatgirl]

Hello. First post!
My hearth stand is complete and I'm working on getting my cooking floor set, but yikes is it turning out to be a pain in my butt!
I'm using the FB insulation board (on a hearth slab that I took great pains to get perfectly flat and level), but this stuff is so inconsistent in thickness that there is no possible way that just notch trowling on sand/brick mud would ever come close to allowing me to get those bricks laid nice and flat. There is a variation in thickness of close to an inch between the warped/high/thick spots on one piece of board and the low spots on the thinner sections of board.
So: A. I guess I'm annoyed since I forked over the $$ and chose this route vs. vermicrete because I thought it would be faster and easier.
and B. I get the impression other people haven't had this problem, and that my experience with this is quite a bit different than the experience of other folks who have used this product....? "Dead flat" is SO not what mine looks like.
Anyway, I've just given up on attempt #2 at laying the cooking floor using just sand/mud as a leveling material on top of the board. ARGH. Now I'm looking at sourcing some vermiculite so I can add an inch or so layer of vermicrete on top of the FB board to level it out. Does this sound like a reasonable plan? I'm certainly open to other suggestions at this point since I'm going to have to start over laying the floor again anyway.
Did I mention, argh?

[mfiore]

Splatgirl,

I have no experience with vermiculite, so can't offer you advice.

Unfortunately, the FB board I purchased was also quite irregular. In spite claims otherwise, It was "warped", chipped, and had significant variance in thickness from one board to the other. I was able to use a mix of dry fireclay/sand to level out the bricks on top.

I've been really happy with the forum, and every other purchase from FB, but share your concern about lack of consistency with this product. Perhaps James will chime in.

[james]

Hi guys,

I'm not quite sure what to say. FB Board is very typical (standard) for this type of insulating board, and we haven't heard of any problems with it -- until today. :-). A majority of the FB precast ovens are installed on FB Board, and we use a very large amount of it building the Primavera ovens -- where we mortar down the firebrick floor tiles with refractory mortar.

In terms of making it smooth enough for the cooking floor, vermiculite is very bumpy and the grains are much larger than the sand or sand/fireclay mixture that most builders use to get their cooking floor level. Vermiculite concrete is also very bumpy in texture -- much worse than FB Board. I guess I have always throught that the sand, sand/fireclay or refractory mortar layer between the cooking floor the FB Board provided the ability to smooth out any bumps or imperfections.

We will definitely talk with our producer and ask that they take better care with the finish surface and consistency on FB Board. They have made changes we have asked for in the past (including making FB Board more dense and rigid after seeing the first trial pieces).

I will let you know what they say.
James