Building wood fired pizza oven: masonry Q's

[Adios Pantalones]

Building a woodfired pizza oven that will sit on a stone catenary arch. I poured a 6'x6'6" slab, 6" thick yesterday. I know that the concrete will be at about 1/2 strength in 7 days- do I really have to wait that long to start laying stones? I'd like to get the arch form made Thursday, and start slapping rocks Friday. I understand the stated advice, but in practical terms- am I OK in 4-5 days to get a start?

I turned my shard pile into the bottom layer of gravel. Cracked stuff, ugly stuff, a whole set of dishes...

 

[ewdudley]

We always figured 4-6 days for half-strength depending on temperature. I'd say waiting three days for 33% strength would be plenty for what you're talking about doing here, you won't be putting much weight on it, plus it will be reasonably well distributed.

(Be sure to keep the surface moist for a week or more.)

 

[yooperdave]

pics pics pics

 

[semipro]

Did you use any rebar/remesh or add fiber to the mix?

 

[Adios Pantalones]

Rebar. Thanks for the advice!

 

[semipro]

Even with rebar I'd be a little worried about cracking given your description of the structure you plan to put on the slab and the nature of the fill under your slab (pottery and high organic content soil or maybe that's sand?). The arch will put weight on the outside and none on the inside resulting in a buckling force on the slab.
If, however, you plan to use stone to fill the arch temporarily during construction, the load on the slab would be evenly distributed.
Also, concrete strength is dependent upon a lot of factors, water content being one of them. If you poured a relatively wet mix the ultimate strength will be less than rated.

 

[Adios Pantalones]

Even with rebar I'd be a little worried about cracking given your description of the structure you plan to put on the slab and the nature of the fill under your slab (pottery and high organic content soil or maybe that's sand?). The arch will put weight on the outside and none on the inside resulting in a buckling force on the slab.
If, however, you plan to use stone to fill the arch temporarily during construction, the load on the slab would be evenly distributed.
Also, concrete strength is dependent upon a lot of factors, water content being one of them. If you poured a relatively wet mix the ultimate strength will be less than rated.

Thanks. There is gravel under there too, but it's not as interesting as smashed pottery. Average moisture- I did read up a bit first. Good thoughts on weight distribution

 

[ChipTam]

Sorry, I don't have any suggestions regarding your construction question. However, you might be interested in another wood-fired pizza oven which is the heart of a new restaurant near out summer home in Newfoundland. The restaurant is called the Bonavista Social Club and there are photographs and information about the stove at their web site. By the way, their pizza is to die for.

ChipTam

 

[joes169]

I'm a masonry contractor, and can tell you that it's not uncommon to start building on a footing the same day with no repercussions.

I've built a few wood fired pizza ovens in the past, although it's been a while. I always used Buckley/Rumford kits, although there is a bunch of instructions available online to build your own. (Which I'm sure you know by now)

I'd be interested in seeing pics as it comes along..........

 

[Jags]

I'd be interested in seeing pics as it comes along..........

I'd be interested in eating a nice slice of pie.

 

[AK13]

Can't wait to see how this comes out. I'd love to see a farther back shot to see where this is going. It kind of looks like you are building it out in the woods!

Also, I'd like to know the total cost of materials when you are all done. Those Rumford kits are spendy.

 

[Adios Pantalones]

After laying my first course, I feel like this will require a lot of mortar. Is it OK to supplement with gravel (making an ad-hoc concrete of sorts) in larger interior spaces? Seems like the logical way to do this.

 

[joes169]

You shouldn't have huge spaces between the units typically, you'd want to cut/chisel the units you're laying to make for a relatively small joint (1/4" to 5/8" is typical). What are you trying to fill? Is this a radius or something?

 

[Adios Pantalones]

You shouldn't have huge spaces between the units typically, you'd want to cut/chisel the units you're laying to make for a relatively small joint (1/4" to 5/8" is typical). What are you trying to fill? Is this a radius or something?

I'm slapping down natural uncut stone. There are spaces 1" wide. If I should cut them to fit better, then I will- I want the exterior natural.

 

[joes169]

I would certainly cut/chisel them to fit tighter. With natural stone, 1/2" to 3/4" joints, relatively equal, is fairly typical. I wouldn't use any stone, but you could use torpedo/concrete/sharp sand if you'd like a more rustic look. How about a picture of the stone you're working with?

 

[Adios Pantalones]

I talked to the guys at the stone yard. They have example walls that are super tight fitting.

They said- look- it's not going to end up like that without a few years experience. Feel free to jam chunks of stone you're chipping into the mortar in larger joints. Stone won't shrink, so it will make stronger interior spaces that you don't see any way. Cutting it all to fit on a home project will make it months of work for a first-timer

 

[Adios Pantalones]

Determining curve of a catenary arch, built form with scavenged wood, then laying stone. Taking me forever.

 

[shmodaddy]

sub'd for outcome.

 

[ironpony]

food for thought. based on what I have read on some stove forums, natural stone can have problems with heat, crack and "explode". hate to see you do all that work and have something like that happen. most I have seen have some sort of fire brick inside. also you need to protect the concrete floor with firebrick the concrete will not stand up to the heat .I cast my oven out of high temp refractory in five pieces. I know you have kilns and have probably got it figured out but just wanted to mention it in case.

 

[begreen]

Is this going to be elevated off the ground to counter level? Seems like squatting down to ground level in order to peel out a pizza would be a real pita.

 

[ironpony]

appears to be ground level in the picture. I have never met AP, maybe he is really short?? I think he is using it more as an oven than a pizza oven. For a pizza he would want a low dome to reflect the heat down on top.

edit; reread the title it is a pizza oven.......hmmmmmm maybe it is a hillside???

 

[Jags]

I have never met AP, maybe he is really short??

He is an Irish hobbit.

<I kid, I kid.>

 

[Adios Pantalones]

appears to be ground level in the picture. I have never met AP, maybe he is really short?? I think he is using it more as an oven than a pizza oven. For a pizza he would want a low dome to reflect the heat down on top.

edit; reread the title it is a pizza oven.......hmmmmmm maybe it is a hillside???

The arch will just support the oven.

My mom said I was short enough to sit on the floor and dangle my feet

 

[begreen]

Ah, so what we see is just a form for the base? That make sense and will be visually attractive.

 

[ironpony]

I knew you thought it thru, that is going to be very unique. must be your artistic side coming out.