A cast in place pizza oven is heavy enough to require a formed and poured concrete slab. It’s also important to note that it’s very important that your pizza oven cooking floor is level (along with your grill), and pouring a level foundation is a good way to start. In our case, we are installing doors in front of both openings, along with a bottom ledge that will keep water out, so we did not design a slight downward slope on our slab to shed water. If you aren’t adding ledge, be sure the gently slope your slab toward the front to keep water from pooling in your wood storage area.

I’m building a 36″ Duomo pizza oven with a 2″ thick dome, which isn’t crazy heavy. I once built an Alan Scott oven that was 36″ wide x 48″ deep and had a 4.5″ brick done covered with another 4″ of refractory concrete (calcium aluminate concrete with sand and gravel aggregate) and a 4.5″ brick floor resting on a 5.5″ hearth. Now that’s weight, easily 3-4 times heavier than my 36″ Italian domed pizza oven.

Plus, the grill side of the outdoor kitchen is very light. And I live in Alexandria, VA, in the mid-Atlantic, where we don’t get deep freezes, and there is no risk of concrete heave (frozen ground moving and/or cracking the slab), so I decided to keep things simple and pour a 3.5″ slab, reinforced with wire mesh, and no rebar.

We did the forms, mixed the concrete in a wheelbarrow, and poured in a couple of hours.

We’re on our way.