This is both of our first times doing this project but we agreed on a generalized plan of cinder block ”walls” and a concrete slab up top that would need to be able to hold the weight of a brick pizza oven. After finding the area in the yard and leveling it with gravel, we began cutting our cinder blocks with an angle grinder. We found that we wanted it ~4 blocks high which measured 30.5” to be at a good height to cook from.
We next needed rebar to hold the whole structure together. We decided on 11 pieces of 10 footers based on adding 2’ for 1’ in the ground + 1’ above structure to bend based off the 30.5”
We decided to cut 9-5ft pieces for the vertical rebar and 6-4ft pieces for the slab
That was fun :)
We decided we wanted the slab to be ~3ft initially but then we changed it to 3.5ft to fit 2x4 form so cut 1ft off each. They weren't exactly 10' like we thought so we kept the difference in the horizontal piece and the verticals stayed at the set length. We could have bent them but we didn’t simply because we wanted to practice welding. This was my first time so we decided to weld to 90deg to make more precise and for practice
Next we hit the rebar that we welded 90deg angles into the ground and filled each hole with concrete. Cheers. All in a days work :)
The next day we added 2x4's for the top edges. Ours is 62" x 51". We left a little edge to be able to have something to grab and hit to not disturb the form when removed.
We screwed along the bottom of the wood every 6-8" with 3" T-20 screws (see box above)
They work really well for removal. Also screwed 2 on each corner to keep the edges up and determine each was square.
We waxed the form with Clark's stone and concrete wax to make it easier to remove
Next, we put the crossbar rebar in and tied it up while we waited 30min for the wax to adhere. Based on the size of the slab and the 5 gallon bucket size, we estimated we needed 7 buckets and with using a ratio of 6:1 Perlite: Portland cement. We did this and landed short so I had to sprint to the store twice for more materials. oops. We ended up close to 12 buckets. We initially did 3 more of perlite and one more ½ bucket of Portland cement but was just a little short so I made one more batch of 1 Perlite and 1/6 Portland cement ( ~2.5” in our 5 gallon bucket)
Total amount (in 5 gallon buckets) = 10 perlites + 1.66 Portland cement
The water was added in the wheelbarrow and mixed with the perlite until it felt like a good consistency. Then it was dumped into the form and spread, patted to ensure it wasunder and around all the rebar nicely. Due to not having enough initially, we made a quick decision to go from 3.5” slab to a 3” (ironic, right) slab so a notch was cut out of the board to ensure it was level to run across it. Once we got it all level, we let it sit ~1 week and then removed the form boards
And that is the base for our pizza oven. Please don’t hesitate to ask any questions :)