Is ceramic fiber insulating board worth it?

[maburton]

I am building my oven and want to make it correctly, but I dont have $ to waste. I just attempted to check out of the Forno Bravo store and to purchase 5 insulating boards and a roll of blanket, the bill was $220 with $120 for shipping. Is the boards and blankets worth $340???

[beaglestorm]

Re: Is ceramic fiber insulating board worth it?

Make sure you call FB directly to ask for a shipping quote. Sometimes the online shipping cost calculator gets it wrong.

[gjbingham]

Re: Is ceramic fiber insulating board worth it?

I'd say yes! Having to do it again, I'd pick the boards over vermiculite (for the floor) in a second.

[james]

Re: Is ceramic fiber insulating board worth it?

Don't forget that vermiculite isn't that inexpensive. The FB board and blanket costs are pretty comparable with the cost of loose vermiculite. An extra $75 blanket on top replaces 3-4 bags of vermiculite, which, depending on where you buy it, can cost $80+.

Plus, they are more efficient and are easier to install.

Sorry for the sales pitch.... :-)

James

[Ken524]

Re: Is ceramic fiber insulating board worth it?

I have to agree with our Brick Oven Merchant . The blankets are definitely the way to go. I am using vermiculite on top of the blankets. If I did it again, I would skip the vermic and just buy more blankets! I have used about 5 bags of the stuff at $20 a pop. That would have bought a lot of very efficient blankets.

I also think the ceramic board is worth it. Far easier and faster to work with than vermiculite.

[thebadger]

Re: Is ceramic fiber insulating board worth it?

I Agree too.

I did both for my hearth. I poured 3 1/2" of perlcrete mainly for extra height and then I put the 2 inch Iso board on top. It was a lot easier to level the brick on the board than would be on the perlcrete. I also bought 2 blankets so I can go with less "loose fill"

Net, the only "specialty items" I had to purchase were the boards/blanket. I was lucky enough to get everthing else from Lowes/HD and my local brick yard.

Hope this helps.

Dick

[dusty]

Re: Is ceramic fiber insulating board worth it?

I am afraid I must agree too. Even if you skip the fiber board, the blanket is a must. So if you are going to order a blanket or two, you might as well get the boards at the same time.
I didn't use the FB board under my oven - just vermiculite and concrete. My oven holds heat pretty well, but now I realize that I loose most of my heat through the floor. I did get a blanket and will probably get another one by the time I'm done.
Easy for my to say, however, as I live in Cal. right down the road from Forno bravo.

dusty

[maburton]

Re: Is ceramic fiber insulating board worth it?

great advice, bad news is FB is out of the floor boards for 4-6 weeks. I guess from your advice, I should put my construction on hold?

[Frances]

Re: Is ceramic fiber insulating board worth it?

Ah well, this might be one of those situations where some of us need to chip in to say how fantastic our ovens are with the vermiculite insulation underneath...

Seriously, my oven is insulated with a good thick layer of vermiculcrete and it works really well, I am completely and utterly pleased with it. With the FB board underneath it might work a bit better and loose heat more slowly, who knows? But after firing up I can use cook with the retained heat for three full days - that's not too bad!

It probably depends how patient a person you are vs. how much the niggling thought of what your oven could do if it were different will bother you. If it were me, I would order the insulating blanket for on top of the dome now, but go with Vermiculite underneath the oven.

[jcg31]

Re: Is ceramic fiber insulating board worth it?

Anyone who hasn't used the insulating board under their floor and just went with the vermiculcrete over the concrete slab should take a temp reading of the ceiling of their wood storage area when the oven is up to temp. I went with a little more than the recommended amount of vermiculite/portland cement mix on the build. When checked after reading a post from CJim I was at 180 on the ceiling of the wood storage when the floor surface was at 800. I have since insultated underneath which helped but I am certain I am still losing efficiency.

Go with the boards!!! When spread over the pizzas and time it will amount to pennies.

Jim

[gjbingham]

Re: Is ceramic fiber insulating board worth it?

That's wierd Jim. Mine stays cold to the touch underneath the hearth until probably 5 -6 hours after firing the oven. 12 hours later, its around 100 - 110 degrees F. That's with 4 inches over vermicrete under the floor of the oven. I still have trouble maintaining a really hot floor for any length of time without having a pretty hot fire burning on the side. That's why I would recommend 6 inches of vermicrete for the insulation hearth vs. 4. I'd still recommend 3 inches of Isoboard first though.

[Wlodek]

Re: Is ceramic fiber insulating board worth it?

I went for the boards. When I calculated the time of pouring the vermiculite-cement, added the number of costly ways I could botch the job and compared it all with just unwrapping the boards and putting them on top of the supporting board/slab there was no comparison ... The proper boards are quite pricey in the UK, but I still think they make a lot of sense.

W.

[maburton]

Re: Is ceramic fiber insulating board worth it?

I ordered the FB boards and they will be used.

Is it overkill to place the vermiculite concrete under the boards? I know you can never have too much insulation, but is it worth the trouble?

What will the temperature get up to under the FB boards? Does anyone think that it could get as high as 200 degrees?

What are some alternatives that others have tried under the FB boards to further insulate them from the concrete slab? alternatives other than vermiculite concrete?

to get to a 41.5" cooking surface, I only have 2.5 inches to use for extra insulation like the vermiculite.

has anyone used asbestos insulation under the FB boards?

[Wlodek]

Re: Is ceramic fiber insulating board worth it?

I ordered the FB boards and they will be used.

Same here!

What will the temperature get up to under the FB boards? Does anyone think that it could get as high as 200 degrees?

A quick calculation (steady state) assuming 5cm (2") of oven floor refractory (1.31 W/(m K) - like brick) and 5cm of FB (0.1 W/(m K) - slightly pessimistic), internal oven temperature 400C (673K), heat transfer coefficient of 20 W/ (m2 K) (standard for brick to air - assuming that FB is exchanging heat with the ambient air or sat on a thin cement board and the ambient temperature is 17C - what we have right now) the temperature of outer surface of FB is 323K (50C)

has anyone used asbestos insulation under the FB boards?

I wouldn't. Not healthy, not even legal in many places.

Yours geekily,

W.

[Ed_]

Re: Is ceramic fiber insulating board worth it?

A quick calculation (steady state) assuming 5cm (2") of oven floor refractory (1.31 W/(m K) - like brick) and 5cm of FB (0.1 W/(m K) - slightly pessimistic), internal oven temperature 400C (673K), heat transfer coefficient of 20 W/ (m2 K) (standard for brick to air - assuming that FB is exchanging heat with the ambient air or sat on a thin cement board and the ambient temperature is 17C - what we have right now) the temperature of outer surface of FB is 323K (50C)

That's so fantastically geeky... I love it! The scary part is that it makes sense.