Igloo insulation options

[rlf5]

I plan on going with the igloo style for my oven, but was wondering how exactly I'm going to insulate the dome and finish it. I know for sure I'll be using a ceramic blanket, but I'd really rather not have to deal with making up any kind of insulating concrete if I don't have to. Is it acceptable to use just the blankets and then a couple layers of stucco, or will that be too susceptible to damage? I had planned on maybe 3-4 inches on the sides and 5-6 on the top for the ceramic blanket. Thanks for any advice for or against.

[rlf5]

bump. Anyone?

[thebadger]

RLF5
Check the plans but I think you can... James says you can use one or both or a combination. If only blanket I think you would want at least 3".

I'm using 2" (3" on the apex) of blanket plus 4 inchs of perlcrete.

The insulating concrete isn't that tough to work with... I would use some "poultry netting" so the stucco can adhere to.

Dick

see my pics in "thebadger build"

[dave d pizza lover]

i wanted the dome exposed, what i did was put blanket over dome followed by 4 inches verm insulating crete (put on in 2 aplications ) then followed by a finish stucco . after a few pizza partys developed hairline cracks in the finish stucco from expansion / contraction . wondered what to do then remembered a product we use on chimney crowns called crown coat . its a brush on sealant that goes on at about 1/16 th inch thickness . its flexible , waterproof and spans existing small cracks . when dry it it a nice gray color . my ultimate plan is to clad the dome in a thin venneer stone but in the mean time i wont have to worry about water infiltration . if you want more info ChimneySaver - The Leader In Chimney Protection

[Dutchoven]

You could go without the vermicrete and just do the stucco...however I think you will be a bit more pleased if you do a layer of vermicrete. It is lighter weight and should not compress the blanket insulation as much...then the stucco coat.
All the best!
Dutch

[nissanneill]

Personally, I don't see a problem with making vermiculite cement insulating over the thermal blanket. You will need some chicken wire and a little patience but not difficault to apply.
It will not only add to the insulation (which would have little to do if you plan on such a thick layer of blanket, BUT would certainly use a thickish layer purely for a substantial base for your stucco layer. Other wise, your stucco layer will damage quite easily and you will still need to get it to cover the soft flexible wool surface.
In my Pompeii construction, I used only a 1" blanket layer and 3" of vermiculite topped off with a thin stucco layer. No heat loss when the oven is over 500˚C, so it does work and work well.
You can view it, and the reccommended method of application at:

http://www.fornobravo.com/forum/f21/...-4-a-2045.html (Neill’s Pompeii #4)


Neill

[70chevelle]

My oven is going to be enclosed under a roof. I plan on using 2" of the blanket insulation. Could I just use perlite or vermiculite and loose fill the void between the roof and the igloo, or do I need to mix it with concrete?

[rlf5]

Ok I think i've settled on a plan. I'll have 2" of blanket on the sides and 5-6 on the top. Then a 1.5-2" layer of percrete and 1" layer of stucco. Hopefully it will have enough integrity not to damage.

[rlf5]

First layer of ceramic blanket.

[asudavew]

I covered mine with about 2 layers of 1/2 blanket.

Then I built a screen covered structure with about 6-8 inches of space around the dome. Then I filled the space with several bags of perlite and vermiculite.

I've just got to the finishing portion. I've started with the chimney. I am going to cover the "loose" vermiculite with chicken wire followed with about 2 inches of mortar. Then I will top it if off with Stucco.

The reason I did it this way.... was because I wanted to keep the dome shape, BUT I wanted the insulating properties of loose vermiculite. (The cement has to lower the insulating value)

The screen has stretched some, so I've added more verm. But once I get the mortar layer on.. it should be pretty stout. The top will need more filling because some has fallen down the sides. So in essence, by procrastinating my finish out, I've benefited ie. thicker insulation on the sides and when I top it off, thicker insulation will coat the top as well.

I've got some pics if you want to see what I mean.