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-   -   stuccoing dome over insulation details? (http://www.fornobravo.com/forum/f7/stuccoing-dome-over-insulation-details-16696.html)

skinnydoc 09-12-2011 07:37 PM

stuccoing dome over insulation details?
 
hello... I'm getting closer to getting the oven on top of my constructed base, exciting! (should the hearth dry for at least a wk before loading it with the oven?)

Once I mortar the dome joints and cover with insulation, how does one put a stucco surface on top of the 'squishy' surface of the insulation? I understand you can use the metal stucco lath available at home depot, but l'm not getting how it all stays together to allow the stucco to be applied artfully? is everything wired together somehow? is the lath somehow anchored to the hearth?

I'd like to make this vaguely aesthetic, without having to start over when I mess it up.

Any help appreciated.

Ben

Les 09-12-2011 09:45 PM

Re: stuccoing dome over insulation details?
 
I formed the dome with rebar and then wrapped it with chicken wire. I filled the gap with the vermiculite/portland and then added some mortar on top. I tried to use the lath but it failed miserably.

Wiley 09-12-2011 10:29 PM

Re: stuccoing dome over insulation details?
 
Ben,

Many of us who built domes used some sort of rebar birdcage affair to which we tied our wire to support the stucco. It makes it easier to shape the quasi-hemisphere dome shape.

Here's a link to my thread which shows the birdcage I built for my WFO. It was time consuming but made the actual task of stuccoing fairly easy. And at over three years so far no cracking.

http://www.fornobravo.com/forum/43/s...html#post38564

Hope this helps,
Wiley

david s 09-13-2011 01:54 AM

Re: stuccoing dome over insulation details?
 
Lots of builders cover the blanket with a layer of vermiculite/cement/water to get a nice shape, then stucco over that.

emsoven 09-13-2011 04:03 AM

Re: stuccoing dome over insulation details?
 
i did not use a fire blanket but only 4 inches of vermiculite concrete as my insulation then chichen wire and concrete render . if i was to build another oven i would let the vemiculite concrete fully cure and dry out totaly before i rendered my dome . i have added some pics of my vermiculite layerhttp://www.fornobravo.com/forum/members/emsoven-albums-vemiculite.html

HeidiL2011 09-13-2011 08:22 AM

Re: stuccoing dome over insulation details?
 
Hello,

Once you use the metal lath to help form the shape you want your oven, you can use rebar ties to tie down the lath. Then you can apply the stucco directly over the lathe.

Thanks,
Heidi

Gazza_46 09-13-2011 10:11 AM

Re: stuccoing dome over insulation details?
 
Hi all

Please excuse my ignorance i am a newbie after all but "Lathe" i have seen many references to this mythical beast but have as yet not stumbled across a description, where i come from a lathe is a metal / wood turning machine ...........please help!

Thanks

Gazz

david s 09-13-2011 12:54 PM

Re: stuccoing dome over insulation details?
 
Chicken wire is easier to shape. You can also cut it into short pieces which can be placed, overlapping each other under the stucco, as you go.the smaller pieces cope with the compound curve (curving in both directions)

skinnydoc 09-13-2011 02:39 PM

Re: stuccoing dome over insulation details?
 
thanks for the responses.... I can see I'll have to get creative, great. :D

so consensus is I need to make some kind of pencil rebar armature over the insulation? I see in the installation manual they talk about drilling 1/4" holes in the hearth to anchor the pencil rebar. Then cover with chicken wire.

does the gap NEED to be filled with vermiculite? the 3in ceramic insulation is spec for this oven, so more insulation, which may have some benefit for residual heat (I plan mostly pizzas, so high heat), is not strictly called for. Seems like some air gap would be fine, assuming my armature is strong enough to hold the stucco and abuse.

(the thought of having to mess around with another fill, e.g. vermiculite and cement, finding it and buying it, is giving me a headache.)

where does one get vermiculite BTW? I doubt its at the local HD.

thanks!

Ben

Wiley 09-13-2011 06:58 PM

Re: stuccoing dome over insulation details?
 
Gazz, it should be spelled lath, try a search of plaster and lath and you should get more info than you ever could need. Modern lath is a form of expanded metal where a sheet of metal is slit in a myriad of short slits in one direction and then pulled/stretched 90 degrees to the slits.

Ben, vermiculite is fairly common at nurseries and places that sell stuff for the garden. Our local "True Value Hardware" carries it but it can get spendy if purchased at such places. You can also get perlite at nurseries, it's sold as a soil additive for much the same purpose that one uses vermiculite (ie: hold moisture and lighten dense soils). Vermiculite is often used for insulation and in ground pool installers use it (beware some is siliconized so it is water repellent...not what you want if you are mixing it with cement and water expecting to make vermicrete)

Hope this helps,

Wiley


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