next step after insulating

[cecilB]

We are getting ready to put the insulation on the dome - we are using three layers of the ceramic blanket. But before we put it on, we want to make sure we are ready for the next step immediately in case of bad weather.
We are planning on putting steel mesh or lathe over the insulation. Over that portland cement? And then over that, stucco? Should there be any space between any of the layers of "stuff" ?

Thanks
Cecelia

[Jed]

Re: next step after insulating

Hi Cecelia,

Mix your Portland cement with some vermiculite or perlite - 5 part vermiculite or perlite, and one part Portland, and enough water to make a mix that is like a thick oatmeal. This mix will do two things. First it will create the final shape of your oven, and develop a structure to hold your stucco. Second it will add a bit of insulation, although with the blanket you are installing it doesn't look like you need more insulation. Put this mixture on top of your blanket about two inches thick - the steel mesh will help support and add strength to the structure. It will take awhile to set up solid, but it will set up and be a solid structure to support your stucco finish.

Then stucco the dome, with the stucco mixture that you like best, in the color you want. Install the stucco directly to the vermicrete / perlcrete.

Good luck with your build!

JED

[100million]

Re: next step after insulating

Make sure you cure the oven before the insulation and between the insulation and the metal lathe I would use alum foil like I used in my build.

Look at the pictures and see what I did

Chris

[cecilB]

Re: next step after insulating

Thanks, Chris and JED.

So, right now we've been curing the oven - some crackage but it seems from everything I've read, it's nothing to start over about.
I'm waiting for the inside of the dome to turn white during the firing.

Then we wrap the whole thing in the blanket insulation. Then alum foil? THEN metal lathe?....What kind of foil? Just normal almuminum foil like you get at the grocery store?
Why?

THEN the verm/portland mix? Then cure some more?
How do I know when I can put the stucco on?
How many layers of stucco?

Too many questions!!!

Cecelia

[100million]

Re: next step after insulating

Grocery store Alum NO NO NO

It looks like this

The alum Foil Aluma-Foil Radiant Barrier - Gaiam

and alum foil tape Buy 491-3x50 3" Foil Tape | Tape Product 491-3x50

you can find it at a HVAC heating and cooling business

Tell them what you are doing and they will give you a partial roll and it wont cost a lot

After you cure and insulate and stucco you dont need to cure again YOU ARE GOOD TO GO..... 2 coats of stucco and you can GET THAT FOR FREE at a Stucco Contractor becasue they ALWAY have left overs from there jobs and have to pay to throw it away and just keep 5 gallon buckets just sitting around,,,,,Just call them and ask if they have any stucco left over from jobs they have done in the pasT...... My stucco contractor have 50 pales in there warehouse.... I did have to choose from those colors. But he gave me 4 pales i needed 3/4 of one to coat 2 coats


Not to many Question :P

HAGD

[kebwi]

Re: next step after insulating

What purpose does the aluminum foil serve?

The conventional Forno Bravo build would be:
-brick
-blanket
-optional lathe/chickenwire
-vermicrete
-stucco

Note I said option on the lathe. If you build the vermicrete in thick belts starting from the bottom, each belt rests on the one below it and no matrix is required...but it certainly doesn't hurt.

I tried to cure my after the ceramic insulation but before the vermicrete. I understand your concern about not leaving the ceramic exposed for too long because it'll just get wet again. Fire it a once or twice (I did, got hoards of steam coming through the ceramic), then go to the vermicrete stage.

It doesn't really matter if you cure with the insulation on since all of the insulation is porous and will let moisture escape, including vermicrete. Only the final (presumably waterproof) stucco is a concern in this respect. You could get the vermicrete in place, then fire the oven several times before going for the stucco. Throw a tarp over it when you aren't using it to keep the rain out.

BTW, conventional stucco isn't waterproof. I used surface bonding cement (Quikrete sells such a product), super-powered with an acrylic fortifier additive, which in several layers should be just about waterproof. I was thinking about adding additional waterproofing over the SBC (something like Thoroseal), but to be honest, after having applied some of it (I'm not done yet) it seems very very water resistant. I can't even properly mist it to apply the next layer of SBC because the water won't stick to it...so I think this stuff is might darn waterproof.

...but yes, get your oven pretty well cured before the stucco stage. The water will have as much trouble going out through that layer as it will have going in.

[kebwi]

Re: next step after insulating

the word is Conventional Forno Bravo.... they use to fight wars with bows and arrows in the old days......I think with all on the added Technology we could start calling them STATE of the ART Forno Bravo Ovens

Are you suggesting the Forno Bravo plans are so antiquated that they precede new advances in technology? They're only a few years old. If you think the Forno Bravo plans are incorrect, then perhaps James should change them...but I don't think referring to it as "coming up to date with modern techniques" makes much sense.

I was simply summarizing for the OP what the FB plan prescribes since she seemed confused on that point. No insult intended.

[fxpose]

Re: next step after insulating

I have a question: Is the vermicrete layer absolutely necessary between the blanket and the stucco?

George

[100million]

Re: next step after insulating

Are you suggesting the Forno Bravo plans are so antiquated that they precede new advances in technology? They're only a few years old. If you think the Forno Bravo plans are incorrect, then perhaps James should change them...but I don't think referring to it as "coming up to date with modern techniques" makes much sense.

I was simply summarizing for the OP what the FB plan prescribes since she seemed confused on that point. No insult intended.

I never said they are plans are incorrect, James has done a great job....BUT if you ask james tell me about your first oven and what you do different now you WOULD BE SHOCKED to see the differents. These designs have been around for 1000's of years....

Just an example....... the alum foil then metal lethe idea is a added idea and one mans idea...... Using Sto or dryvit vs conventional stucco with an acrylic fortifier additive is just an upgraded Idea......or how about using Heatstop50 vs Poormans mortar.....All these ideas are additions to your oven

That is why I called it STATE of the ART Forno Bravo Ovens


I am all good with your comment

[kebwi]

Re: next step after insulating

No, the vermicrete insulates and smooths/shapes the exterior appearance of igloo styles (but not enclosure styles). With enough ceramic fiber, you don't need additional insulation, and shaping the exterior is merely an aesthetic issue, so it isn't required...but sufficient insulation of one form or another is required.

Of course, that's just my view. Other people may pipe in and point out things I have missed or forgotten. Maybe I missed something.

Cheers!

[100million]

Re: next step after insulating

I have a question: Is the vermicrete layer absolutely necessary between the blanket and the stucco?

George

I would say yes becasue you are building the last outer layer to form the doom to look symmetrically.

the other reason is that if you us STATE of the ART Stucco.... ..... it is only a thin coat...... and if you use Conventional Stucco you can build it up to what ever thickness you want to ( it is like using Colored Mortar with additive for water proofing in it )

[fxpose]

Re: next step after insulating

Thanks guys! I realize the dome would be much easier to form/sculpt using a thin layer of vermicrete. It's just that I have clearance issues where I don't want the final stucco layer to go beyond a certain point. I basically have 3" of blanket and perhaps another inch or so to finish the dome exterior.

George

[kebwi]

Re: next step after insulating

Yeah, I was being pretty precise in my previous answer. While the vermicrete is not required to make the oven cook properly (assuming you have sufficient ceramic insulation), it is nevertheless a stretch to call it optional if you build an igloo enclosure because you've got to mold and shape the exterior appearance somehow, and if not vermicrete, then how? So yeah, it isn't very optional.

[cecilB]

Re: next step after insulating

Oh my!
I'm not really confused...yet - Just ignorant on this stuff...Ok, I looked at your build - what are the "pins" in the insulation blanket?
I will be telling my son what he needs to do, and I have to sound like I know what I'm talking about! ha ha.
I also looked at the alum foil. Funny. I thought you were just talking about aluminum foil.
Is that something I can get at lowes?

So the mesh or lathe goes OVER the foil?
and then after that goes some verm./portland. ( I feel like an old pro at that!) and the mixing of mortar mix.
Anyway....THEN stucco - call a stucco company and see if I can get some of their leftovers? We just bought four bags at Lowes yesterday, but I can return those!
I wonder how many stucco people there are in this neck of the woods!

By the way, your oven build is so nice looking! I would LOVE to start over. heh heh heh - but I'll have a chance whenever we redo this kitchen!

Yes, and I was looking at the chimney pipe - we're doing a 42" oven - the 36" x 8" at Forno Bravo for 230 bucks?!?!?! They have what seems to be exactly the same stuff at Lowes for 97.00 so I bought that one - but I need a cap. I was referred to a local HVAC company for one....I suppose I could also get the alum foil there and tape?

This is all new thinking to me, I just want you to know. I was just figuring out the brick cutting and laying and was enjoying it when winter came...and then an expecting baby in July! So I've been rather out of commision and have been tying to focus on more...."ladylike" things like, ahem, sewing and stuff....ha ha. Now, although I won't be WORKING on the oven, I have to be able to TELL my son with conviction what he has to do! And I want to kinda hurry up so I can practice making pizzas and have it down for 3 of my kids graduations at the end of the month. Is it possible?
sigh.

That's why I seem confused!
Thanks,
Cecelia

[kebwi]

Re: next step after insulating

While you're researching stucco, you may as well considering something like Quikrete Quikwall Surface Bonding Cement and its sister product Quikrete Acrylic Fortifier. It is an alternative to conventional stucco which has many nice properties. First, it has little fibers in it that act like a lathe/mesh, providing structure and lateral strength to the final product. Second, it contains materials which actively repel water. Several people on FB (myself included) have used it.

I will have to leave it to someone else to comment on more basic stucco materials. My guess would be that (relative to surface bonding cement) they are more likely to crack (no fibers) and more porous to water (no hydrophobic compounds). Of course, you can buy the fibers loose and mix them into your stucco and the waterproofing issue can be handled by many options, either additives to the stucco or final layers coated over the stucco.

Don't you just love being paralyzed by a glut of options?