Oven Build - From Start to Finish

[B.Sitt]

Hello,

I am a long time reader, but first time poster to the forum. I am going to attempt to detail my recent oven build from start to finish with the limited photos I took (I always forget to take pictures and wish I took more!). I will try to do it without rambling too much over a couple of posts within this thread, but hopefully it will be of some interest to the community. Now on to a my wood fired oven adventure!

This was my first ever attempt at building a brick oven and thanks to my wonderful family I was given time over the past 7 months to build this oven. I am a bit of a DIY/ build it type of guy, but my current occupation is a travelling hospital auditor, of sorts. Prior to starting the oven my wife asked I not start any new project for a while, but a long weekend with nice weather here in the lowcountry of South Carolina in February and getting news we would be having our 2nd child had me ready to start building the oven before I lost what little free time I had left to ever build the oven. I convinced my wife somehow and she asked if I start it could I have it done by our daughter's B-Day in July, and I told her of course, or at least I will try to do it in 5 months! I had studied the instructions downloaded here at FB and had read through many of the builds documented on this forum.Thank you all for posting your experiences allowing someone like me with limited knowledge, serviceable skills, an obsession with buying new tools and used materials, and a dream to figure out how to construct a wood fired oven for my outdoor living space.

My oven is a 36 inch design with the higher style Neapolitan dome. I honestly had never heard of this type of oven, but came across it during internet searches while trying to figure out a "fire feature" for our outdoor living space. Initially, I was going to build a fire pit, simple and easy, but I worried about the hot ashes getting on my wooden garden features. Then I thought about building a traditional fireplace and thought it would be nice, but not very useful. Then when I found the idea of the wood fired oven and I knew this was what the space needed!

I did make an IT and tried to make a jig to cut the bricks to minimize joint V's. I do not have a pic of the the IT, but I simply used a small castor wheel as a base and attached an extension type wand with a magnet on the end.I attached a piece of angle iron on the end of the magnet. The castor wheel was attached to the center of a piece of 1/2 inch fiber board using epoxy. The fiberboard served as protective floor covering while building my dome and was easy to remove in the end. I never could get the saw jig and HF saw set up properly and got tired of dealing with it and wasting energy on perfectly cutting brick angles, so I just said screw it and cut the bricks straight in half.

My oven base was built as a dry stack of cinder blocks with 1/2 inch rebar in each corner and every other core with wet cement. I did wet set the bottom row of the blocks to the patio slab. One thing I did not do here is to ensure there were drainage holes out of the backside, as the patio pitch ran directly into the dam I was building. Instead, I waited until the very end of the entire job to drill in some drainage holes and this was not a fun job! I poured a 4 inch concrete slab with 1/2 inch rebar inside (I must say that I NEVER could have physically done this job without a cement mixer from HF bought on thanksgiving for $180 - super deal and no I do not work for them - HAHA!). I had to do the vermicrete insulation in 2 - 2 inch layers because I ran out of materials. I mixed this in a wheel barrow by hand and it was tough at first to get moisture consistency between the batches my tub could hold. I bought the amount of vermiculite the instructions called for, but it only did half of what I needed. In retrospect I hand compacted the mix down and maybe it was supposed to be left more just spread out, loose and airy and that is why I need twice as much and became 2 layers (as you can see in the photo there are 2 layers of vermicrete)?

Also, I used 1/2 inch concrete board under the hearth slab concrete and just left it in. I also decided to run the board all the way to the end of the cinder block stand, instead of cutting it short of the edge and allowing concrete to fill in the remaining open cores. One thing I thought about then, did not do, and now wish I had was driven 3 inch backerboard screws through the concrete board before pouring the cement so it would have "grabbed" into the cement hearth better.

A friend of mine helped me set the floor and start the first course. The floor was set in a mix of sand, fire clay, and water and at this point had finally decided to build the oven dome on top of the floor. It just seemed simpler and less brick cutting. I was at just under 3 months into the job when the floor was set. I was still hoping to get this thing done in time to for the birthday party after the 4th of July somehow...

[B.Sitt]

I used half bricks stood on end as a “soldier” course to start building the dome. There were 11 courses total after this I believe. I found the IT to be a very useful helper and guide for setting bricks. I chose to mix the homebrew mortar using a 5-1-1-1 sand, Portland, fireclay, and hydrated lime mix and found that screening the sand helped a lot with setting the bricks. It was extremely hot and humid weather so I ended up cutting back on the lime by ˝ as time progresses because the mortar would set up within seconds of placing a brick. I have since developed cracks in the upper half of the dome and possibly less lime in the mix made the cracking more likely to occur?

As the oven took shape, I chose not to install any type of heat break, for simplicity sake on my part. I didn’t realize though, I was building the oven opening a little different than most. I built the inner arch walls and chose a stopping point, but then built the vent walls jutting out from the exterior of the oven wall brick. I noticed many ovens build the oven walls into the vent walls, leaving one single width dimension (aside from a small overlay for door) all the way into the oven. I eventually had to use a grinder on the oven opening edges to open it up slightly and round off the edge.

One mistake I quickly realized I made after I set the final 3 courses was that I continued to use the bricks cut in half. I did not cut each of these bricks again any smaller until the final few bricks I cut to fit in as key stones in the final course. Also, I hastily made a sand form with what I thought was a very thick cardboard base to finish the final rows and it allowed some bricks to be set in deeper than others. I had to smooth it all out with a grinder to make the dome ceiling bricks even and smooth the mortar joints. I honestly was amazed it all held together after I pulled out the form, since I jacked up the last 3 courses!

I used coated chicken wire to connect the oven courses to the vent wall course every few bricks high. I finished the dome the before the last week of June. I also used about 5 inches of vermicrete as the exterior oven insulation. I gave the insulated oven about 12 more days to cure and dry. I have developed cracks in this oven and think this limited cure time possibly increased my cracks. Really, the oven was covered from rain and it was very hot and humid, but I do not think the oven was ready for me to fire when I did. That vermicrete holds A LOT of water!

[B.Sitt]

I struggled with how to build the oven vent and chimney. My friend that earlier helped with setting the floor built the vent and chimney using granite and 4 fireplace panel inserts cut to form the sides. The exterior of the vent walls and vent was covered with stacked flagstone and I added a 3 ft. stainless chimney pipe. This eventually blew over in a storm and dented my vent cap, because we only set the chimney vent pipe base bracket into the wet mortar mix. After blowing over in a storm I included bolts with anchors set in epoxy for the vent pipe base eventually install some bracing directly to the oven.

I cut and installed the granite countertop next. I tried to pay attention to creating a small pitch away from the oven with the granite, kind of all around. It is consistent around most of the oven and nearly dead level on the front piece. At this point I was right on schedule to make the July birthday party for my daughter, and had about 4 days prior to have the curing fires. My daughter even gave a hand smoothing out the vermicrete with a pool float tool!

I did not have the amount of days for curing fires as given per most guidance. I did four days and did my best to keep the oven at low temperatures for the first 3 days of fires. The 4 curing fire day I let the fire get up to over 750F, likely higher at times. I felt like I stayed within the low temp ranges the previous 3 days, but again, this possibly assisted with the cracking.

So, as I’ve done all of this work to get to a stage in about 5 months to cook pizza for this birthday party, when the idea of cooking pizza for a group of people for the 1^st time ever terrified me! My wonderful loving wife allowed me to back out and fall to plan B – Little Caesar’s! Pizza, Pizza! (and wings!) (Eh, it was a 2 year old’s birthday pool party so it made life sooooo much less stressful for us!)

[B.Sitt]

After the party and throughout the summer I shut down having any more fires as I had developed some cracks in the dome previously and just concentrated on using free time to finish the exterior. I covered the dome with stucco lathe and included a base layer and another thin layer of stucco. Next job was the dome’s and base’s finish material.

The same friend came up with an idea of using crushed glass and trying to make a polished cement countertop type of look. This consisted of 3 each 25# buckets of crushed fire glass (brown and clear, bought blue also, but left out the blue) and a mortar type mix called Ardex 77. First though, we tried to stick the fire glass onto the stucco layer of the dome only using a bag of regular mortar mix. This was not successful as the glass was too heavy and the mortar mix not sticky enough. After mixing glass and mortar in the cement mixer, we had to build a screen and hose off the glass to try another time with a better, stickier product.

The Ardex and glass was mixed together and stuck on the dome to about ˝ inch thick. Next my pal used a 4 inch diamond wheel cup attached to an angle grinder to grind down the glass/ardex mix to a smooth finish. This work created the thickest nastiest cloud of white dust I ever seen. It got everywhere and I had to scrub the granite countertops with grout remover to remove the residue when it was all said and done. Next, I used a concrete polishing kit on my angle grinder to polish the dome exterior.

[B.Sitt]

I finished the base exterior walls with flagstone all around and a little bit of granite in the entryway to underneath the oven. I sprayed the polished dome and flagstone work with 2 coats of high gloss stone sealer. This spray ended up drying on the granite counter tops and they felt like the cover of a basketball. I ended up then having to scrub the countertops with goof off and scrub and scrape off the wax like sealer.

Once again, my friend came to help with the oven door this time. For this, we used the same fireplace insert panel from the oven vent and he cut and beveled the door to best fit the oven opening. I included a heavy duty shelf bracket as a handle and a thermometer.

Now, come fall after my 2^nd beautiful daughter was born, I had 2 low temp fires slowly built to 350F, and then decided it was time to make pizza. I got the oven floor up to around 700F throughout the day while watching football. We used pre-made dough from the grocery store and made 2 pies. They were DELICIOUS! Since, I have attempted to make my own dough and it was good, but will improve. Also, re-lit a small fire next morning and made the best quiche I ever ate!

I have come now to find a great satisfaction after building this oven and will plan to build another someday…bigger and better. I made mistakes for sure and it was tough work, but a great experience that will provide some interesting family enjoyment and yummy food! I was worried about the cracking as it came through the final dome exterior and I have found cracks elsewhere. I have since decided to leave it be, cover it from the rain, and focus on new tasty recipes!

[B.Sitt]

Here are a few more photos... Again, thank you to those on this forum and at FB for sharing valuable information to help give me ideas for building my own. Enjoy!