Floor inside dome installation

[Eiknarf]

Hello All,
Very excited about finally getting started on my Tuscan oven. I have two questions, perhaps better left to 2 threads but this is my first post to not entirely sure, here they are:
1. I am going to fit my oven floor inside the dome, and I plan to use FB board insulator underneath. I have the FB install booklet, but the only pic they show with the board base is for the floor extending under the dome, therefore the foam board also extends beyond. Now, looking at the cross section diagrams from the book, it shows the brick floor fitting inside the dome, but the board extending to the outside edge of the dome, so the entire dome sits on the board. This just doesn't seem like the best way to go, your dome is mortared together but not mortared to the floor(which seems fine), OR to the hearth, just kind of floating there. Even thought I understand the weight will keep it stationary, I feel like the best thing to do would be to have the the board and brick cut to fit inside the dome, and have the first course of the dome stand upright (like for a Neapolitan oven), but extend all the way to the hearth and be truly mortared in place. Are there any issues with this??
2. I plan to build a 42". We occasionally hold event at the ranch and want to be able to cook 100-200max pizzas over a couple hour time span. Do I need to go bigger??

Thank you so very much for your help!

[rand18m]

Re: Floor inside dome installation

I too am interested in the answer to question #1. I will be starting my oven soon and I plan on using the FB board and having an inside floor. My assumptions are the same, that the board would be cut to fit the brick and first course laid against hearth.

[SevenAcre]

Re: Floor inside dome installation

Hi Eiknarf and rand18m,

You want the both the floor and the dome resting on your insulation board. Your entry arch and entry floor should also be on the insulation. This is very important. As others have put it, "think of the entire oven encased in a bubble of insulation". If the dome or any part of it are in contact stand you are essentially creating a heatsink that will draw temperature out of your oven.

hopefully this addresses the question you were asking.
-j

[GianniFocaccia]

Re: Floor inside dome installation

It is critical that both dome and floor rest directly on top of insulation. The more insulation the better. Neither the dome nor the floor is mortared to the insulation, and float on a thin bed of fireclay/sand mix, if required, to establish a level surface. Both rely solely on weight to remain stationary. Any direct contact between dome/floor and the concrete support slab below will result in immediate and long term heat loss through conduction. The consequence of this is poor oven performance and unnecessary wood usage.

Floor bricks cut inside the dome need to have 1/4" gap between the floor and dome to allow for expansion. This gap soon fills with ash and is forgotten.

200 pizzas in 2 hours is a pretty tall task, even for a seasoned pizziaolo. What is that? Like 25 pizzas every 15min? Check with Windage, he has an 81" monster with an incredible soapstone floor. I'm now on my second hundred pizzas and have never cooked more than one at a time.

Best advice I can offer is instead of 'build as you go', first sit down and draw up your oven. Free Sketchup software download makes this task more than doable. Start with what you want your finished oven to look like and back into the details, including dome dimensions, entryway style, flue configuration and materials. This will cause you to address many construction elements that are far easier to remedy on paper than later on. You will also be able to budget for oven stand size, insulation requirements, etc The FB plans are nothing more than a rough guideline and its in your power to take your oven to the next level.

[jeeppiper]

Re: Floor inside dome installation

Regarding question #2....I have a 42 inch oven and we had a "make-your-own-pizza-party" at our house. We did nearly 100 pizzas that afternoon ('twas a lot of fun) The bottleneck is really more about oven management and technique, than oven size. A hot oven (with live fire) can cook a pizza in 1-2 min. My 42 inch oven can handle 3 pizzas comfortably with the fire going on one side. I could squeeze more pizzas in the oven, but some pizzas would end up too close to the flames and end up burning...For me, 3 pizzas is my personal max.

Doing the math...say 3 minutes for 3 pizzas...that's 60 pizza's per hour. You are going to be exhausted after doing 100-200 pizzas...but it is worth the challenge.

I think you want to size of your oven based more on your anticipated "normal usage" rather than basing it on your occasional largest usage..... I like my 42 inch oven....If I had to do over again, I might consider a slightly smaller one.

...just throwing in my three cents.

[ftaylor74]

Re: Floor inside dome installation

I am at this point in my construction also.

My question regards the sand/fireclay mix. Should this mixture have water in it? if so, how much.

I recently picked up about 50 lbs of pottery clay slip, and have been drying it out in preparation for mixing with sand. Its currently about the consistency of tooth past. It seems that it could be troweled well enough, but perhaps not stiff enough to keep the floor bricks nice and level.

Also... is it better to lay the soldiers first, or cut and lay the floor and then put up the soldiers. I'm not sure which way to go just yet. What is best practice.

Also, it seems that at least one floor brick ought to be mortared (or otherwise fixed) in place, so that while laying the surrounding floor you have an immoveable stop. What would the harm be in doing that?

Thanks in advance
Regards

[GianniFocaccia]

Re: Floor inside dome installation

FT,

Some trowel sand/fireclay mix wet - I went dry because of some builders' challenges with bricks soaking up mixture moisture leaving a gooey mess.

Cut the floor first and then start your dome. A large percentage of builders now are skipping soldiers and going with horizontal first courses. I did this and would do the same again.

No harm in mortaring a brick to act as a corner stone, but again, the weight of each brick will hold them stationary.

If you can, read through a number of builds and see what others have done. There is no right or wrong way, but you do have the opportunity to do it your way. Many times it comes out as good or better than the next guy...

If you haven't already, you may want to start a build thread so you can share pics of your progress.

[ftaylor74]

Re: Floor inside dome installation

Thanks Gianni,
I will go with your recommendation on starting with the floor. My original plan had been to cut the floor bricks (after laying them out and marking them with a template). Then I would reposition the template unto the insulation layer, and lay a course of 1/2 height soldiers butting up to the template. Finally, I would set the pre-cut floor bricks. That was before I read in another post on this thread that I needed to make sure that I have 1/4 inch of space between the floor and the wall of the dome. .

Anyway, I'm about ready to start cutting bricks and am getting pretty excited!

Thanks again!

[Greenman]

Re: Floor inside dome installation

The gap between the floor and the dome is the way to go. Allows for expansion and keeps the integrity of both safe.

[rand18m]

Re: Floor inside dome installation

Greenman what's your opinion on not having floor inside dome? Especially considering an oven of only occasional use?

[NCMan]

Re: Floor inside dome installation

I don't think it makes a bit of difference which way you do it and personally don't think it's worth all the time and trouble to cut all those floor bricks. Just don't let your floor bricks project too far away from your oven walls and be sure to insulate them well. You'll be fine either way.

[rand18m]

Re: Floor inside dome installation

Thanks for the response, if I don't do the inside floor I will lay out FB board rectangular and cover completely in firebrick for looks, the oven will be inside a room you can walk in, (storage etc), the outside of oven entrance will be a rock wall in outdoor kitchen. I will want it to look slick around the dome since I will see it occasionally. (maybe a bit anal, maybe) Anyway seriously considering laying out board and firebrick symmetrical and start walls on top of firebrick. Thanks again!

[Greenman]

Re: Floor inside dome installation

I formed my decision to have the floor and the dome separate with advice from the forum. The logic sounded sensible to me and that is what I did.

I think i would do it again since it is not difficult to do and makes sense to me. I don't see a downside to having the floor separated from the dome.

No doubt it would work either way.

[rand18m]

Re: Floor inside dome installation

Thanks for the reply. Would you suggest one 2" layer of insulation board or two?

[SevenAcre]

Re: Floor inside dome installation

Hi rand18m,

I too cut my floor to fit inside the oven. My logic was anything extending under the dome bricks and outside them was just more thermal mass, and would therefore have to be heated and insulated while serving no real purpose. Why burn the extra wood and spend the additional time firing? The cutout took less than an afternoon, and I will certainly get that time back over the life of the oven.

As for insulation, if it's just a question of two or four inches, do four for sure. I have two. My oven works great, and I have decent heat retention (225-250F 72hrs after fire); however, if I put the infra-red thermometer on the bottom of my slab when firing (aiming up through the wood storage) it consistently reads 20-35 degrees warmer than the ambient. Not a lot, but considering that is through 4 inches of solid concrete and re-bar after two inches of FB board, I know its taking a significant amount of energy to get there. I'd rather that go into the oven. Dry split Oak in the California Bay Area goes for 450$ a cord.

-j