Emergency help needed for WFO under contruction

[Abouna]

OK, we've started our build of a Pompei style 48" (or so) oven. loosely based on the FB plans.

We had a great time without any hitches forming things up and putting in our base.  We poured a 3.5" foundation slab and then proceeded to a 4" hearth slab.  Unfortunately this is where I think we might have screwed up.  We read several places to mix 1 bag of vermiculite with one bag of portland.  We thought this would be a 5:1 mix but it's looking like it;s more of a 3:1 mix, the vermiculite was 3 cu. ft/bag and the portland is 1cu.ft..  

Is this going to cause us a problem?  We don't want to go to all this work and have an inferior oven, pizza and break baking both.

Please advise.

PS- My wife started a thread on FB at the beginning of our build but I encouraged her to come over here.  Just seems like things are a little less FB slanted (obvioulsy).

[shuboyje]

I've responded over at fornobravo, but think you made a good move coming here.  IMHO there is a lot of bad advice given on forno bravo due to very closed minded thought.  They want everyone to build exactly what's in the plans, and will tell you rediculous untruths to get you to do so.  Sadly you see very few pizzas posted there by the most vocal who give out most of the bad advice.  Here you will find people who actually use their ovens too cook great pizza and honestly share their experience in doing such.

[Abouna]

Jeff,

Thanks for chiming in.  My suspected sentiments exactly.  Plus I've been a semi-lurker here much longer.

At this point my wife is pretty anxious, already thinking we're going ot have to chip our slab away!  I'm of Mediterranean descent, as such my attitude is that, we Americans (especially semi-fanatical hobbyists) tend to over think and over nit-pick everything.  I'm half German and half Lebanese;  my German side wants the oven to be empirically perfect, my Lebanese side says "we'd have built the thing out of mud and bricks back home and tourists would flock to the results".

I'm leaning toward assuming the thing will work excellently as is.  Of course, before we put the work into the dome I'd like a little bit of assurance on that point!

[Ev]

Looking at your photo, the next step would be to pour the hearth slab using just concrete, no vermiculite. If you included vermiclite to your 4" hearth slab, you'll need to rebuild it. Vermicrete alone has no strength without solid support under it. After that comes the 4"vermicrete layer, or the rigid insulation board. I forget exactly what they call it. It should look something like the first few posts on my build thread here.http://www.pizzamaking.com/forum/index.php/topic,11155.0.html
If that's where you are now, and it's just a matter of having the right ratio of vermiculite and portland, I'd make sure it's right before proceeding with the dome. It's relatively cheap and easy to replace it now. Although 3 to 1 my work just fine, peace of mind is a very valuable thing.

[Abouna]

Looking at your photo, the next step would be to pour the hearth slab using just concrete, no vermiculite. If you included vermiclite to your 4" hearth slab, you'll need to rebuild it. Vermicrete alone has no strength without solid support under it. After that comes the 4"vermicrete layer, or the rigid insulation board. I forget exactly what they call it. It should look something like the first few posts on my build thread here.http://www.pizzamaking.com/forum/index.php/topic,11155.0.html
If that's where you are now, and it's just a matter of having the right ratio of vermiculite and portland, I'd make sure it's right before proceeding with the dome. It's relatively cheap and easy to replace it now. Although 3 to 1 my work just fine, peace of mind is a very valuable thing.

Sorry, please see the original post.  We've already poured both slabs already hence the emergency.

It's looking like we're going to have to add a 2" insulator baord to correct our mistake.  It means the final hearth will be 2" higher, but that shouldn't be a problem.

[Ev]

Ok, I wasn't sure from your post which slab was in question. I looked on FB to see if there were other photos but I couldn't find your thread. Sounds like you have it figured out. Enjoy your new oven.

[Tscarborough]

"I've responded over at fornobravo, but think you made a good move coming here.  IMHO there is a lot of bad advice given on forno bravo due to very closed minded thought.  They want everyone to build exactly what's in the plans, and will tell you rediculous untruths to get you to do so.  Sadly you see very few pizzas posted there by the most vocal who give out most of the bad advice.  Here you will find people who actually use their ovens too cook great pizza and honestly share their experience in doing such."

I haven't noticed that all, who do you have in mind?

[Tscarborough]

OK, I was PM'ed.  Let's be clear that Forno Bravo is a commercial site for a manufacturer and seller of a particular style oven.  They allow almost anything to be said on the site, but the reality is that it is biased towards pompeii ovens.  Some of the posters are zealots, and some are one-oven experts, but overall the forum is a very good resource.  I have only built one oven with my own hands (and it ain't round), but I do have masonry and refractory knowledge and experience.

I do see what Shuboyje points out, but please do not let that limit your use of that resource.  There are just as many of that particular brand of zealotry on this forum about pizza, and it certainly does not dissuade me from using this (wonderful) resource.