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I've built one oven using all the great information on this forum, but I only had a few months to enjoy it before our family decided to move. So, after a bit of delay caused by complaining neighbors and a slow-to-approve HOA, I’m breaking ground on oven number #2 at our new house and would like to share the process with the forum and highlight what I’m planning to do differently.
My original build was a 42 inch corner build, igloo-style in the gulf coast area. It was based largely on techniques from the classic JRPizza, Mongo and UtahBeehiver builds.
A few things I learned last round:
Thinks I’ll keep the same:
-Monroe
My original build was a 42 inch corner build, igloo-style in the gulf coast area. It was based largely on techniques from the classic JRPizza, Mongo and UtahBeehiver builds.
A few things I learned last round:
- V-grooved calcium silicate vs. flat block calcium silicate: Flat block cal sil was not readily available at the nearest Distribution International, so instead of paying the freight charge to have flat block shipped, I went with the v-groove version. At the end of the day I doubt the v-groove vs. flat makes a noticeable difference in heat retention, but the grooves made installation a bit more difficult. The material tended to break apart at the grooves and it was difficult to shape.
- Foundation slab — I started my build as we were adding an addition to our house so I was able to piggyback my slab pour on to other concrete work being done. I learned no one really understood what I meant by “pizza oven”. It took a few conversations with my GC before he was convinced I needed a six inch slab with rebar reinforcement. (And he was still blown away when the oven dome started to take shape.) We eventually got the slab reinforcement right, but the second problem was that with heavy rain in the gulf coast a sloped slab is standard…so that is what the contractors poured and it hadn’t crossed my mind to ask for something different. This created two challenges — Laying blocks was more difficult than it needed to be requiring a variable thickness of mortar to level each row of blocks. And, I could have used the firewood storage as a swimming pool. I drilled a few holes where the blocks met the slab to allow water to drain, but it was an imperfect solution and a level slab would have saved a lot of hassle
- Cutting concrete block - The corner build required a few blocks to be cut at a 45 degree angle. I tried scoring blocks with a chisel and hammer and cutting with an angle grinder before eventually getting a diamond masonry blade for my skillsaw. It was messy work and probably shortened the life of my saw, but by using the saw and a speed square as a guide, I was able to make clean 45 degree cuts.
- Entryway staining — I originally built the floor between the dome arch and the outer arch out of firebrick. It was fine, but it quickly became grease stained and the area never got hot enough to burn clean so I decided to remove the firebrick and replaced it with soapstone. This required cutting the slab of soapstone into a very awkward shape using a combination of skillsaw and angle grinder (both with a masonry cutting wheel and a grinding wheel). Huge mess, huge hassle. End result looks good (if you don’t look too closely), but if I had thought ahead it would have been so much easier to build the arch directly on the soapstone slab rather than cutting to fit after the fact.
- Igloo vs. dog house enclosure - I really prefer the igloo look but the next owner of this oven is going to be fighting against the weather. The under-oven insulation is foam glass topped with calsil board, with weep holes in the slab and I thought that would solve the most likely water issues. But it turns out water intrusion from the top down was a bigger issue than from the bottom up. The dome was covered with 2-3 inches of ceramic blanket, chicken wire then 1-2 inches of perlcrete, 1/2 - 1 inch of stucco, and then coated with Thoroseal cement-based waterproofing. Despite that, after a few months of use, the Thoroseal developed small cracks and there were signs of water intrusion in the interior of oven. If I hadn’t moved away I would have probably tiled the dome and maybe that would have solved the issue, but given the heavy rains in the gulf coast, a dog house style enclosure would have been a smarter decision and is what I’ll be going with this time.
- Oven size — We live near extended family and regularly cook for 12+ people, but I’m confident a 39 inch oven is enough for us. The 42 inch oven was great — ample floor space for multiple sheet pans, room for 2-3 pizzas (but I never found myself cooking more than one at a time) and was still easy enough to work. But, most of the time I was using the oven, there was plenty of unused floor space and in the few instances where the oven was full (cooked Thanksgiving dinner entirely in the oven), things cook so quickly it is easy enough to swap items in an out as needed.
Thinks I’ll keep the same:
- Beveled and tapered bricks — Don’t know if it’s necessary, but cutting bricks is fun.
- Heat breaks on the inner arch and at the floor
- Wide opening - 20 inch opening might shrink to 19 inches with the smaller oven size, but it’s essential to have it wide enough for an 18” sheet pan to pass through.
- Deep vent landing - It’s a lot of fun to start a fire directly under the chimney and lay a grate over the coals to grill. A deep, wide landing gives plenty of room for that.
- Indispensable tool - Truly is
- Oven floor cut to fit inside of dome - Cutting bricks is fun
- A split brick for the first course - This prevents there being a joint right at floor level where your peel can catch
- 5 block high oven stand instead of the often recommended 4 blocks - We are a tall family and I like having the oven opening at chest height (about 51”) so there is no bending to look into the oven.
- Whitacre Greer Firebrick - I agonized over medium duty vs. light duty and alumina content, etc. But went with the easy to find Whitacre Greer bricks. They worked great. Easy to cut with the harbor freight tile saw and seem durable.
- 5 inches underfloor insulation and 4 inches dome insulation
- 8 inch double walled Duravent stainless chimney - Very easy to install. On the 42 inch oven, the four foot chimney had some smoke out the front on start-up (probably due to sometimes using green wood). This time the chimney will only be 2 feet tall. I'd prefer 3 feet but my neighbors disagree.
- More precise brick cutting - I used the angle guide that came with the harbor freight saw along with a magentic angle guide for the blade to try to cut the angles recommended by the dome spreadsheet calculator. I also I realized too late that I'd set my brick size a 1/4 inch off in the spreadsheet calculator. I will build a cutting jig both for dome bricks as well as tapered arch bricks to try to cut more precisely.
- Cleaner brick work - There are point where I did not pay attention to vertical joints and I saw cracking on the inside of the dome where joints lined up. I also got impatient toward the top of the dome (and clean up gets harder) so there were a lot of messy joints. I don't think more consistently sized bricks or cleaner mortar work affect the operation or even the lifespan of the oven, but the dome just looks cooler when everything is nice and neat.
- Better finishes -- I didn't put much thought into the finish of the last oven and will be spending more time on aesthetics this time.
-Monroe