42" Pompeii Corner Slab dimension HELP!

[Denamontini]

Hi!

We are building a 42' corner Pompeii oven in Coastal Virginia. Dang, this is taking over our lives!!! We have been reading and reading, but are mainly using the E-book as our guide.

We planned on a 70" x 70" slab. Now I see conflicting information. PLEASE HELP!!! What should the dimensions of our slab be and why?

[JRPizza]

We put our 39" er on a 70 X 70 slab with a chopped off front. I think there would have been room for a larger oven - I think I have about 4 inches on the sides. If you check out my build you can see how we placed the oven.
Edit - thought I was posting on the same thread that Russell replied to - sorry!

[Denamontini]

Thanks for the reply! I didn’t mean to post twice— but I was convinced the first one didn’t work. I’m assuming there is a delay. I’ll check out your build too! I appreciate the help!

[JRPizza]

I understand your concerns - I also was using the FB plans and noticed the discrepancy between hearth size for a rectangular vs corner build. This is the time to take a deep breath and figure out some more details before you start pouring concrete. A 70X70 should be fine, but details like the shape at the opening end (flat vs curved) and oven placement should probably be firmed up before you set something in stone (literally). If you have any questions after looking at my thread please ask. I also have cad files for my build and could easily do a few quick layouts for you if you wanted.

[Denamontini]

Thanks so much!!! Do you feel the corner base is significantly better? We have a blank slate and can just angle a rectangular base for similar effect. Now, with a pallet full of supplies, we are rethinking this whole thing! Haha

[JRPizza]

We built a corner cause we had a corner spot and to maximize room it seemed like a better design. Also planned to maybe build off the sides, which I believe the corner design is superior for. We didn't but the shape makes it easy to butt up a picnic table on one end and a kitchen island on the other. I'll check my archives - think I may have a 42 inch corner already done - will let you know.

[JRPizza]

I attached a file I did for one of our builders where he built a ~43 inch oven, and a file of my 39 incher. He used a slightly bigger stand so you might not need that large of one. I also attached a link to his build as he documented it well and there is much discussion on using the cad files and program you can point your friend at. Let me know if you have any questions.
PS, the files are zipped as the extension is not one that the forum recognizes.

[SableSprings]

I came to the same decision as JR did, that the corner build offered some significant advantages to our location. Mine is a 39" dome with a barrel vault facade. I made some wings on my top slab to accommodate some prep work and incorporated into the stand, two pull-out carts. The carts were planned to give us extra below storage (wood & entertaining supplies) as well as creating large work spaces for prep and post-bake needs (cooling breads, cutting pizza, etc.) The biggest mistake I made in creating the top slab was in not giving myself enough room between the back of the oven and the covering, screened den structure walls.

Nothing wrong with staying flexible on your design at this point...you will use all those supplies (and probably more... ).

[david s]

Whilst the corner build has some advantages there are a couple of problems if building an igloo style. If the oven is tight into the corner it is difficult to work around the sides and back, especially when you come to finishing the surface of the outer shell, particularly at the base. The resulting space in the corner is also inaccessible and becomes a great collector of dirt and debris. One solution is to integrate the oven into the side walls with vermicrete.If building a dog kennel style the existing side walls can reduce labour and materials as well as dealing with the useless space at the back of the oven.

[UtahBeehiver]

While my base is larger than a 70 x 70 I do have a thicker dome and also a 12 work surface in the front of the oven as well allowing for a 3" stone veneer over the CMUs. So it depends on a lot of different factors. JR is good with CAD but I just sketched out using a pencil and grid paper. It is easy to change on paper but once the concrete flows it is a different story.

[JRPizza]

For me it was a case of "Trust but Verify". I used the cad layout to give me confidence that the slab was going to be big enough, but after I poured the slab I still made a cardboard layout to verify that the location the cad program told me to put the oven center was the correct placement. I later used the cardboard template to place my floor bricks and make sure they lined up with the opening the way I wanted.
It was very early in my planning (I think post #3) that I realized I needed to figure some things out before I just started pouring concrete. The ovens are somewhat adaptable/forgiving, but planning it out now will help prevent work-arounds, corrections and compromises down the road.

[Denamontini]

As of 2:26pm today we have an 80”x80” square dug in the yard for a corner placement. (We will cut one corner at like 63”). I did a few sketches, but there is a lot about the vent/chimney/landing that I don’t fully understand yet. I cannot visualize the pieces going together in those spots. Our weather doesn’t look good enough for a concrete pour anytime soon, so that buys me more time to think about it.

[Denamontini]

Hi All!

Planning this pizza oven has taken over my life! Haha! I'm sure you can all relate. I have poured over plenty of builds on this site. Has anyone done a vermiculite base in the modern era? (2016-2018) It doesnt seem like it. Or do I just cough up the money for ceramic fiber board? I was trying to keep this project "around" $1000... so I wanted to know where people saved money and where people splurged. On the bright side, I did get a pallet of free cinder block!

I will start a build thread once I actually pour the base, right now i am planning, planning, planning and waiting for nicer weather.

Thanks again for the help and guidance! This will likely be my one and only build!

[SableSprings]

Interesting point of view on the use of Permicrete/Vermicrete vs ceramic board in the oven base. I think it's good to consider those of us folks in the "older era" that are still happy and using our insulating concrete base ovens for all these years...

I think over the years, the price has come down on the ceramic board and those wishing to keep costs down realize that using the board cuts down the build time, decreases the height requirement (2" ceramic board is still a bit better than 4" of insulating concrete), and is much more convenient. I knew the board was available, but I couldn't justify the cost when I built in 2009. It does seem to me that there have been quite a few very successful builds in the modern era (and posted in the Forno Bravo community forum ) that have used the insulating concrete/hard matrix method. I'm sure you are correct that the percentage of builders now using the ceramic board is significantly higher (and probably now the majority), but again...the insulating hard matrix method has been around for centuries (Roman use of pumice and cob oven straw/clay mixes for instance) and I suspect they will be viable options to reduce costs for a long time to come.

The bottom line is that now is a wonderful time to build a WFO...you have LOTS of material options and a LOTS of experience to draw on from this community. We're all here to help you be successful (and happy) with your build...but it's your pocket book and available time.

[david s]

The ability to adjust strength and density easily in your own cast insulating slab is a great advantage; eliminating the water is the problem.