Driveway Slab Foundation or Frost-line footing Foundation

[artistadimattoni]

I am ready to start a pizza oven project, but I am not sure if I should use an old driveway slab or go through the work and expense of a frost-line footing. The frost-line depth in my area is 30-36 inches. The old driveway slab is in excellent shape, no cracks and good size with a 5 inch depth. Is this adequate for the block base, insulated slab and a brick facing?

[UtahBeehiver]

Does you city require a permit or inspection for an oven? If so, then you will be bound by the local inspectors. That said, monolithic pours with good gravel substrates for drainage have been successful in colder climates. The key is how good and deep is the base course under the driveway. These ovens are really heavy and there have been a few on the forum that are trying to resolve settling bases. If there is any doubt on compaction or material under the existing slab then you need to take step back and reconsider using the existing driveway. You mention insulating slab but not a hearth, you will need a regular of rebar reinforced hearth then your insulating slab or insulating material.

[artistadimattoni]

Thanks for the reply! I am out of city limits, so I don't think that will be an issue. I will check to see what the code is within city limits.
I am intrigued by the Beehive name and picture in your user ID. Have you built a beehive kiln before?

[UtahBeehiver]

Beehive is part of the State of Utah flag and the pic is one of the old Pioneer charcoal making kilns in the state. Originally, I was a starving art major (ceramics) in school then changed changed to Engineering, go figure. Back to you driveway, 5" of "reinforced" reinforced concreted with a compacted and gravel sub-base will work. Were you there when the driveway was installed?

[artistadimattoni]

Driveway: No, the driveway is at least 50 years old, but unused when we bought the house 20 years ago. I don't think there is a lot of rock underneath the slab. It is very stable in its spot, though. I am sending pictures. I am not 100% sure of using this spot, but would love to get started with the pizza oven! I value the input!

Beehive Kilns: I have done brick sculpture until recently at one of the country's last beehive kiln factory in Cayuga, Indiana. Colonial Brick Corp. had to close due to the economy, but manufactured some of the best brick including clinker bricks. I plan to use some of their brick in my pizza oven once I figure out the foundation!

[UtahBeehiver]

You just have to use your best judgement. These ovens are really really heavy so caveat emptor. Hate to see you go through all the work of building one of these beast just to be hampered by a uncertain base. The solid base is the core support of your oven.

[RandyJ]

I would have to agree with Utah. You will have to make a judgment call and Although we can offer advice it is you that have to live with it. As had. been said these ovens can get very heavy. The one i built weighs in around 10 tons. So make sure it will support the weight.