solid pour foundation and stand

[fsucpa]

My concrete guy is suggesting that I/he form up the whole cabana floor and the floor for the pizza oven and the vertical forms and the floor of the oven itself for a single pour. So, to clarify, that would be, instead of cinder blocks for the pizza oven stand, with a 4 inch thick concrete raised slab, his form guys would form it up for a single pour. the stand would be solid concrete,with, I assume, rebar and fiber for extra strength, no blocks. What are your thoughts.

Tom

[asudavew]

Re: solid pour foundation and stand

Others have used this technique.

It works fine. It's just a preference thing...

A lot of large buildings use concrete walls that are poured flat on the ground, and lifted in to place.

[Les]

Re: solid pour foundation and stand

Dave,

I don't think they are going to do a tilt up, just one single pour.

Tom, as long as the forms are well supported it should work. At the end of the day, I'm not sure you are going to save anything, it's going to require a lot of time to set the forms and a lot of mud to pour - block is cheap and really fast to stack. It does avoid the two separate pours though. If you trust the guy, go for it.

Les...

[Unofornaio]

Re: solid pour foundation and stand

From a labor/cost point of view its pretty much a wash so there is not real savings. Your trading the time spent forming for the return trip to lay the block form the hearth slab and pouring. From a structural point of view this is and acceptable way to do this as long as the footings and joints are adequate. The only area that is in question for me is having a cold joint between the hearth slab and the base does allow for some expansion of the hearth. Then again I'm not that familiar with what temp the the hearth slabs achieve on these style ovens. I know my bread ovens hearth slab would get pretty hot, hot enough to expand considerably but since I incorporated a thermal break I never needed to worry about its effects. I'm not saying you need a thermal break for these ovens I'm just concerned that the expansion of the hearth slab might might put undue stress on the base where the meet.

I know most on here are built with the slab tied into the base with rebar and what not but there is still a cold joint there that allows for some movement. I honestly dont think the hearth will get that hot as to be a concern for these oven.
I think somebody on here has a probe in the hearth slab maybe he knows how hot it gets? Overall I really dont think it is an issue.

[Archena]

Re: solid pour foundation and stand

I thought you insulated the hearth?

[Unofornaio]

Re: solid pour foundation and stand

For bread ovens the insulation is UNDER the hearth slab. For these ovens even though they sit on the insulation layer a lot of heat still transfers to the supporting slab.

[DrakeRemoray]

Re: solid pour foundation and stand

I poured the foundation and walls in the same pour. I poured the hearth slab later and made a thermal break between the stand and the hearth slab. I don't think the hearth slab actually gets hot enough to expand, though I have never measured the heat under there after a long bake. I will have to do that.

Pictures of the stand formation here
http://www.fornobravo.com/forum/f6/m....html#post2653
and the a picture of the formed up hearth pour is here:
http://www.fornobravo.com/forum/f8/n...earth#post2760

Hope that helps.

[Mojoe]

Re: solid pour foundation and stand

For bread ovens the insulation is UNDER the hearth slab. For these ovens even though they sit on the insulation layer a lot of heat still transfers to the supporting slab.

Anyone know why they are the opposite? Insulating layer under as opposed to on top of the hearth.

[fsucpa]

Re: solid pour foundation and stand

My humble thoughts are that on a pizza oven, you don't need mass, you want quick heating that holds that heat for a reasonable time. For an A.S. bread oven, you need lots of mass to heat up and stay heated for a long time. That is why a bread oven takes something like 7 hour to achieve its desired temps, because all that mass is sucking the heat away from the main chamber. This is based upon exhaustive reading, not first hand knowledge, which also leads me to assert that an A.S. bread oven probably couldn't get up to proper pizza making temps. Is that correct guys?

Tom

[BrianShaw]

Re: solid pour foundation and stand

Is that correct guys?

Yes.

[jwnorris]

Re: solid pour foundation and stand

<snip> ... which also leads me to assert that an A.S. bread oven probably couldn't get up to proper pizza making temps. <snip>

It all hinges on the primary purpose of your oven.

An AS oven can cook pizza however, it will take longer to get to that point as the design is such that it takes longer to saturate and holds heat longer.

A pizza oven will cook bread. Just not as many batches between firings.

So, what do you want to do - bake many batches of bread and the occasional pizza. Or, cook pizza, bake a batch or two of bread, and bake a lot of other dishes.

Ultimately these are the questions that one needs to answer before building.

J W

[Unofornaio]

Re: solid pour foundation and stand

. which also leads me to assert that an A.S. bread oven probably couldn't get up to proper pizza making temps. Is that correct guys?

Pretty close except for this part. You can maintain your bread hearth at a high temp for longer than your pizza hearth because of its mass (if you build it that way). So the bottom heat is not a problem. The radiant heat from the fire is also not a problem in a barrel oven but because of its size and shape requires more fuel and the convection that is created is different than a round dome.
A barrel vault oven can be built with the equivalent mass as a Pompeii oven it does not have to have a 1' thick hearth or 10" of concrete on the dome and sides. Likewise you can add mass to a Pompeii oven.
JW makes a good point. The fact of the matter is both ovens can do both but each is BETTER at one thing based on bake chamber design.
Pompeii - Pizza
Barrel - Bread

[Mojoe]

Re: solid pour foundation and stand

Be interesting to see how my barrel oven cooks as I have the insulating layer (4:1 vermic-cement) under the floor bricks... support slab under that.

[CanuckJim]

Re: solid pour foundation and stand

Well, yes and no. My AS high mass oven takes quite a while to get up to bread baking temps, but it will store usable heat for 8 to 10 loads done properly. As for pizza, it is entirely possible to get my hearth up to pizza making temps. In my first attempt some time ago, the hearth was just plain too hot (think 40 second pizza). The main drawback with a barrel vault oven in making pizza is that it is difficult to get the flame to the apex of the dome without making the whole operation too hot.

Jim

[Unofornaio]

Re: solid pour foundation and stand

Hey Jim thought you were MIA.