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]

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]

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]

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]

I thought you insulated the hearth?

[Unofornaio]

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]

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 (From Mailbox to Pompeii in Colorado)
and the a picture of the formed up hearth pour is here:
http://www.fornobravo.com/forum/f8/n...earth#post2760 (New hearth slab design question)

Hope that helps.

[Mojoe]

Originally Posted by Unofornaio

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]

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]

Originally Posted by fsucpa

Is that correct guys?

Yes.