Foundation Slab for the Oven

[joshpizza]

I am planning to built Pizza oven in Fairfax Virginia, so just wondering if i need footing for the foundation slab, if yes then how deep ?

In Virginia frost line is 2 feet.

Appreciate your expert opinion

Thanks

[MarkJerling]

If it were me, I'd take the foundation to good ground below the frost line.

[Pizzarotic]

If it were me, I'd take the foundation to good ground below the frost line.

Sounds a bit excessive for a pizza oven. Check whether your building code allows small floating slabs. Put down a good base and 5 or 6" thick with plenty of rebar.

[MarkJerling]

Sounds a bit excessive for a pizza oven. Check whether your building code allows small floating slabs. Put down a good base and 5 or 6" thick with plenty of rebar.

Yeah well, as I said, "if it were me". But hey, I've only been designing and building for 35 years, so, "if it were me". For my own oven, which weighs around 7 tonnes all up, I've gone about 2.5 feet down to pretty solid ground. That works out to about 410lbs/sq.f.

[Pizzarotic]

If your oven is 7 tonnes then yeah you will definitely want a solid foundation, probably even piers.

[w650gb500]

I’m in northeast PA and poured a 5-1/2” slab on top of a gravel base. No footings or sonotube, just framed with a 2x6 and threw a bunch of rebar and tied it together. So far, so good with the weight of my oven/counter and cabinet on top.

[Pizzarotic]

Nice job! Did you cast the concrete beams yourself? I might steal that method for my next build. Your countertop turned out well also.

[MarkJerling]

If your oven is 7 tonnes then yeah you will definitely want a solid foundation, probably even piers.

The mass tends to be more than most people imagine. I've just calculated mine and even my guess at 7 ton was light!

In mine, for instance, the fire bricks are about 1.5 ton and the brick for the base is likewise about 1.5 ton. The suspended slab, in my case a 190mm thick slab to suit the brick module, is likewise about 1.5 ton, without steel. Then there's the fill between the brick layers, so about 1.2 ton. Added to that, the foundation slab itself 4 ton. 8 bags of fire cement at 30kg/bag, so that's another 240kg. And, about 15 bags of regular mortar at 25kg/bag, so that's 375kg. So, all up, including steel and flue it's more like 10.5 ton.

[w650gb500]

Nice job! Did you cast the concrete beams yourself? I might steal that method for my next build. Your countertop turned out well also.

I went to the local concrete supplier and purchased the lintels from them. They had them in different lengths and have rebar set inside. The concrete counter top was fun to do as it was my first attempt and doing one. There are numerous pix in my build thread.

Good Luck.