Monolithic Slab for Pizza Oven Base

Hello! I’d like to to get started this weekend on my oven, I like the idea of the poured in-place monolithic slab for a base. Anyone have pictures or ideas as to how to make the hearth base insulation cutout ? Instructions for this would be awesome!

Hello, Aaron and welcome to the Brickwood forums!

Three vs. One is an ongoing conversation. It depends on your level of experience with concrete and your confidence in being able to get that (heavy) slab a few feet up in the air.

Here are two FAQs about why the Brickwood base is designed as it is:

  1. I just want to pour it all at one time…
  2. Why three slabs instead of a monoithic slab?

With that said, if you plan to do a monolith, and you’re doing it on the ground, you could simply modify the instructions for the three part hearth (which is cast upside down), and use a single foam insert for your cutout. You’d also want to pay attention to the rebar grids, which are there both to reinforce the structure and mitigate the effects of stress that would lead to cracking.

That’s going to end up being a half ton of slab that you need to hoist up, but I suppose with enough of the right kind of help you could get it done.

Casting it in place on top of the base is more advanced; some folks have said that they have done this but I’d like to know in detail how, and with photos. (Seriously.)

Personally, I stuck to the three-slab method and it worked fine. I don’t see the advantage because the molds are easy to make, it’s all cast at the same time, and effectively you have a single slab when you’re done.

Look at the Anhorn photos on page 4 in the gallery, they’ve posted some really nice photos of their poured in place slab, i’d like to know how they made their void for the hearth insulation. The 3 piece is square only.

Hey Aaron -

Welcome to the forum! I just looked at the Anhorn gallery and I think I’ve figured it out. What you see is one SOLID slab / counter. That etched area in the concrete is where the firebrick / hearth surface brick is being adhered w/ mortar.

Now - here’s where you have to look closely… this install is actually quite genius!

Notice how the hearth cooking surface is 2 layers of firebrick in height? Mr. Anhorn simply created a firebrick “frame” on that first layer, then filled the inside of the frame w/ the insulation material. 2.5" of insulation. Then he installed the 2nd layer of firebrick on top of the 1st layer of insulation. GENIUS!

If you do this - don’t build your pizza oven base 5 cinder block rows in height. Your oven would be too tall if you did that… Just go w/ 4 rows in height as this 2 row hearth / firebrick system is going to add about 6" to the height of your oven.

That’s one beautiful installation. Here’s a direct link for anyone else who wants to look at it.

I do think it underlines the point to say that the Anhorn’s have some pretty serious chops when it comes to masonry. Their work is awesome, and awesome-skilled. They laid electrical conduit under the slab before they poured it, and their forms are carefully thought out.

They took a kit that’s designed for Johnny & Jane Homeowner who are maybe putting two bricks together for the first time ever, and leveraged it using their mad skills to make a breathtaking installation that incorporates the pizza oven. They didn’t need most of the installation instructions—and would have been held back by them. It demonstrates how far you can extend the basic concept.

I think anyone who wants to build a monolithic slab, and has some experience, should go for it. But I stand by the observation that it’s not a first-timer’s technique by any means.

Thanks for sharing those photos, @Aaron!

Jim Anhorn here,

I poured the slab in place because it is a total of 12’ in length with the counter top and it was pretty much the only option. I went 5 rows of blocks high on the base, but my footing is below grade because I wanted my patio blocks to cover the footing. This leaves about 4-1/2 blocks in height plus the 6" counter top above the finished patio. I’m 6’ tall and it is the perfect height.

Brickwood’s reply above is exactly what I did. While the counter top was still wet I roughed up the area for the oven with a broom so the mortar would stick, two courses of fire brick around the outside just wide and long enough for my finished stucco to cover them, one brick thickness of insulation and sand and finished cooking surface on top of that. A full brick width for the back and a brick thickness set on its side for the front.

If I could change one thing it would be to insulate the front also, the front gets too hot without insulation and cracks the stucco. Just last weekend I removed the loose stucco from the front an put on a new coat. My best advice is take your time, this is a large chunk of concrete, steel and brick that weighs thousands of pounds that will be in your back yard for many years. Take your time and do the best you can. As you can see with the unfinished oven all bundled up in the winter it took me two summers to complete.

It’s also a never ending project, which I love, tinkering in the back yard is one of my favorite hobbies. I’ve added two courses of decorative brick to the chimney, a damper and cap to the chimney, a thermometer to the door and a few more decorative brick. I am planning on sending in some updated photos in hopes BrickWood will add them to my gallery.

Good luck and have fun

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Mr. Adhorn,

Well you did an excellent job on your oven set up for sure. And thank you so much for your advice and your pictures too! I’d like to do something like yours but with just one extra area to the right. I’ve done some concrete work but I’m no expert.

Please post more photos when you can, you have a beautiful home and are those labradors in your yard too? I’ve got 2 of my own as well.

I hope to be close to done by Labor Day.

Thanks again!

Your friend,


Jim, glad you posted this. Welcome to the community!

I love that this is a continuing project for you, and especially appreciate your advice about insulation.

Hope you have many, many bakes to come!

I’d like to post more pictures, but all the pictures I took during construction are in the gallery. Some days I got so caught up in building I forgot to take pictures.
I did notice that the direct link in bikerbudmatt’s post above does have a few more pictures than the gallery does. I suppose they had to condense them a bit for the gallery.

Elmo is a Chocolate Lab and Jack is a Flat Coated Retriever.
Sadly they are not with us any more. Jack lost his battle with bone cancer a few years ago and last fall Elmo lost his battle with spinal damage from a previous owner when he was abused as a puppy.
Both rescue dogs and the best boys in the world. We still laugh about the trouble those two block heads would get themselves into.