Learn how to build an amazing pizza oven with an exercise ball!

Wood-fired pizza oven built using exercise ball

Want to know another way to build your own pizza oven? Then have a look at this DIY pizza oven which made use of an exercise ball to create its dome!

Yes, you can use an exercise ball as the mould for your DIY pizza oven. It’s a convenient way for those who already have one at home, and it’s less messy than other pizza oven projects!

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11/29/2022 12:56 am GMT

The detailed step-by-step tutorial below will tell you all you need to know and do, so start gathering your tools, and materials and start making this project!

Is this the kind of DIY pizza oven you would like to build?

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You’ll need these materials:

  • Exercise Ball
  • Perlite
  • Portland Cement
  • Stainless Steel Needles
  • Formica
  • Fire Bricks
  • 3 x5 x 1/2″ Cement Backer Board Durarock/Fireboard
  • Pavers
  • Chimney 4″ x 2′
  • Plywood
  • Duct Tape
  • Plastic Wrap

And these tools:

  • Measuring Tape
  • Ruler
  • Marker
  • Trowel
  • Wheelbarrow/Bucket
  • Cordless Drill
  • Staple Gun
  • Screwdriver

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How to build a pizza oven with an exercise ball!

Wood-fired pizza oven built using exercise ball

Top dome mould builds: So after inflating my wife’s exercise ball, I measured the circumference to figure out the diameter for the circle cut out for my oven project. After a high school flashback, you take your CIR measurement divided by pi 3.14, and it gives you the diameter. I cut out my circle, inserted the ball, and boom – the inside dome was created.

Wood-fired pizza oven built using exercise ball

FYI – There is an image that shows a bungee cord around the bottom of the ball. I had a fear of laying concrete on the top and the ball slipping through. I never used the bungee cord and I just simply inflated the ball slightly more, essentially wedging it.

Wood-fired pizza oven built using exercise ball

Then it was onto the door mouth entrance. So with my dome height of 12.5 inches, I went with a door height of 7.875 high, remember the ancients, trying to aim for a 63% ratio. I wanted to be able to pull the ball or deflate the ball from underneath so I wanted to pull out the door mould as well.

So here is the setup on that. One thing I can say is, take your time. Just like a lot of things that you create that translate to many stages later in a project, the devil is in the details. Take your time to make those things fit better.

I had some trial and error on some things, like the white legs you see under the platform, they sucked and fell apart. I got them from my neighbours’ trash. Also, I never thought it through until I was about to put concrete on the form, supporting the plywood/mould.

When you’re messing with it, pretty much anything can hold it while you play with it. Then it dawns on you, about the weight and awkward shape you have to support from underneath.

Wood-fired pizza oven built using exercise ball

Once the mould for the pizza oven was ready or when you think it is, it’s time to just say go for it and mix up the concrete.

Wood-fired pizza oven built using exercise ball

Concrete mix and moulding to the top dome: So the mix I went with was Perlite/Portland Cement. I also added stainless steel needles for (fibre) strength.

Wood-fired pizza oven built using exercise ball

I used a wheelbarrow and your standard hoe with a chop action. I started with 2.5 buckets of perlite and a half bucket of Portland Cement. Mixed together well. Then I added the SS needles, I saw online that someone said about 5% SS was needed.

I purchased 10lbs so I figured about 4 lbs should be plenty. I hope that overuse is not overkilling that’s going to be an issue later.

Once it was mixed well, I added about a half bucket of water and kept the hose close to sprinkle additional water as needed. Don’t forget that once you have water in your mix, add very little water carefully a little goes a long way. If you add too much water you can always throw some additional dry into it.

Wood-fired pizza oven built using exercise ball

If I were to do it again, I say this now, but at the time it seemed like a lot of extra work, I would have NOT used the ball as a form. Yes, it did work. Yes, it does look great. The thing I didn’t like is that I had planned everything out including the dome thickness and wanted to keep it at 2 inches.

I even made a gauge to ensure proper thickness. But once I started to carefully add the material it just could not support itself going up the sides of the form. The top held, and the bottom/ sides up about 4 inches, any higher it would just slide down and thicken the bottom.

Also, the material feels very odd if you have worked with concrete before, the perlite makes it extremely light, and airy and you feel the need to try to “compact” to the wall and the BALL gives and moves. So if you apply too much pressure the rest of the ball bulges and you see material moving.

So with that being said, I might have put a plaster on the ball, made a positive mould, and then transferred to a negative version of it. I didn’t take any photos of the “during” process for a few reasons: sweating my butt off, frustration trying to keep it from sliding all over, South Florida 90-degree weather, and did I mention sweating my butt off?

In the end, the bottom walls are about 3 inches thick and the sides about two.

Wood-fired pizza oven built using exercise ball

Finish detail on dome top of the pizza oven: So after I had explained that you couldn’t really push or compact the mix too aggressively or the ball would just give and bounce. After a day of curing, I noticed one spot the size of an eraser head where I could see the ball through the wall.

So I decided to skim-coat the outside and inside. I skimmed the outside and after a day of curing, I removed the moulds.

Wood-fired pizza oven built using exercise ball

I had been trying to figure out the best look for the outside of my pizza oven and after I saw the results of the mix I decided to use some of the Portland cement and some SS needles to skim the inside and outside. It came out looking pretty good.

Just remember, water is the enemy. Use sparingly. Obviously, you want the proper amounts to create the cement to the optimal mix, but try not to use too much water in smoothing and whatnot. You’ll find that water might make it easier to smooth out the surface, but the right timing on the concrete (about 5 minutes after applying) and some elbow grease will do the same thing.

Wood-fired pizza oven built using exercise ball

So for the inside and outside I just applied a light thin coat of the Portland and SS needles and made sure I took advantage of the stiffness and worked the mix into any holes.

Wood-fired pizza oven built using exercise ball

Bottom floor mould of my pizza oven: So the top of my pizza oven is done. Now it is time to work on the bottom. Almost all the ovens I saw used either a large terracotta tile or a pizza stone on smaller ovens. I wanted fire brick. I wanted my pizza oven to look nice, serve a function and be replaceable if they crack over time so they could not be “concreted in” like you might see on some larger ovens.

Also, it is important to lay your brick floor in a herringbone pattern. The reason being if you lay your bricks parallel to the door when you slide your peel in you run the risk of catching or chipping a front brick edge. Not good and doesn’t taste good either. Besides herringbone screams quality.

Wood-fired pizza oven built using exercise ball

So I slid the top dome onto a piece of plywood, traced it out, then took my original circle cut out that I made for the exercise ball (giving me the inside circle of the pizza oven dome) and had my two templates.

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