Under construction

[grega]

Hello to all, this is my first post and my first oven. I am SOOOO excited to be able to build this for our love of pizza/ bread/roasting. I have been looking at many designs over the past six mos. or so and have a question or two.
I have seen many that suspend the vermiculite slab on rebar, and THEN pour a support slab????????? Seems backwards to me , from the first time I saw that I thought HUH!!! I am so glad I found this site because the support slab SHOULD go first?? HUH, HELLO!! THEN the insulation slab. I know it is an older design and I'm sure they are fine, but I think the other way around in the new age makes perfect sense to me. That's the way I will do it. I am planning on the vermiculite mix for the insulating slab.

Is pre mix, 80lb. bags (with a mixer of course) ok for the support slab? Rebar and wire will be added of course. That is what I poured the base slab with, and it is beautiful, will this be ok? Thanks in advance.

[splatgirl]

Re: Under construction

yep, bagged mix works just fine.

[grega]

Re: Under construction

Splatgirl, thanks for your reply. I am a bit puzzeled with the insulated slab going UNDER the support slab. is this right? Seems backwards to me,any advice on this? Again thanks so much.

[splatgirl]

Re: Under construction

NO NO NO NO NO!! Insulation ON TOP of support slab, directly under your oven hearth bricks.
Otherwise, all the heat from your hearth bricks would be going straight into the giant heat sink that is your support slab.
I have not been around long enough to know why some instructions said to put the insulation under the support slab, but this is most definitely wrong.

[grega]

Re: Under construction

THANK YOU!!!! I new this was wrong , just didn't make sense to me, after YEARS in construction it just sounded WRONG.
Did you build an oven of your own?
So with the vermiculite and cement mix, isn't it a bit tricky to get it level from being so pourous, I guess you can level it with the fire clay sand mix well enough to set your fire bricks nice and level?

[splatgirl]

Re: Under construction

I did build my oven, yes, but I used the ceramic fiber insulation board and so do not have hands-on with the vermicrete as an insulation layer. From what I understand it is a bit unruly to work with but yes, screed it level and address any finish issues with sand.
A few pics of my build and my work-in-progress enclosure:
Building a Wood Fired Oven - a set on Flickr

[grega]

Re: Under construction

NICE JOB on the igloo!! The food looks YUMMY!! That boy did a great job on the pizza!! I like the effort with the snow blower, someone wanted PIZZA!! Ha! Again GREAT JOB!! I am going with the barrel dome 34x 40 and can't wait to cook in it. Thanks and good luck to you!!

[dmun]

Re: Under construction

You might want to download our oven building instructions. They're free, and pretty comprehensive. You'll avoid a bunch of pitfalls if you read the directions.

http://www.fornobravo.com/forum/f8/p...load-1674.html

I'd pretty much ignore any books/websites/instructions that call for insulating under the slab. Vermiculite concrete works fine, but it's a little odd to work with the first time.

[grega]

Re: Under construction

thanks for the advice, I am concidering laying fire brick as the insulating slab 2.25" and then building the hearth floor, what do you think of this?

[grega]

Re: Under construction

I DID try to down load it, but it didnt work?? Seems other folks have had problems with it also. I would love to look at it, though I am not building an Igloo type. I have concidered the super isol board but I think there are other ways that would work?

[RTflorida]

Re: Under construction

I believe in the Forno Bravo store your have to add the plans to your cart and 'checkout' as if making an actual purchase, even though the plans are free. You are then either directed to a link or are emailed a link (can't remember which) where you actually download the plans.

Firebrick as the insulation layer? NOT a good idea unless you are using INSULATING firebricks (the lightweight, white ones) and are standing the brick on edge so that you have 4" of depth. Insulating firebrick have roughly the same insulating value as perlcrete or vermicrete - so 4" is recommended. Using standard firebrick (regardless of duty rating) will only add more mass...not insulation.

RT

[grega]

Re: Under construction

Thanks for the reply, I am teetering on this insulating slab,i just don't know if the vermiculite cement layer is strong enough to hold the rest of the build, I am concidering the FB board, I am building a barrel dome, I can see that this website leans toward Igloo designs which are very nice, I will bake more than just pizza and want the radient heat for more hours than some designs will produce. Someone said to back 50 loves of bread you will need 50 igloo ovens.hehehe, that was kinda scary to me.

[Tscarborough]

Re: Under construction

I am also building a barrel vault, 24x36. I would keep trying to download the plans though, as the information pertains to both. Most important is the ratio of inner arch height to dome height, but the general construction guidelines will help as well.

I just finished the base and began work on the oven itself. My thread is under my name in the oven pictures forum.

[Tscarborough]

Re: Under construction

If you do the weight calculations, you will see that you only need a compressive strength of 6-8 PSI. The perlcrete is easily that, probably 30-50 PSI.

[grega]

Re: Under construction

Great!! I am working on a 34x40, I like baking pizza but also make lots of artisian breads so radient heat for hours after pizza IS impotant. Thanks for your reply, please keep in touch.