Our last few months have been spent building a cob oven. It’s taken us several months, waiting out rainy weather, gathering supplies, getting hands dirty, rallying troops, but the end result is super pleasing.
This has really been Joel’s baby. Part of the major selling points to our house for Joel was the size of the yard an potential for outdoor cooking. Ever since he was able to use an outdoor oven at an AirBNB we stayed at in Flagstaff, AZ over Xmas, he’d been anxious to get crackalackin’ on it. To build the oven, Joel was mostly working off ideas from Year of Mud and Delicious Magazine’s suggestions from Simon Brookes.
In choosing a location for the oven, we were lucky to have a(n unused) bocce court on our property. This meant we had a flat area that did not require leveling or other prep to start on.
Once a proper spot was staked out, we planned what we wanted to do with the base. We decided to build it out of wood thinking it would be less expensive than using cinder blocks (whether or not this is true is debatable). The final cost building the base was ~$250. We constructed the base by laying out the 4×4 wood pieces and using 3ft corner braces to provide hidden structure from the inside. Once the base was created we filled the inside with urbanite and other random material to be used as a heat sink. We sourced 98% of the fill material (a shi* ton of material) from the “Free” section of Craigslist.
Once filled, it was time to get prep the cob. The cob was a mixture of sand, clay, straw, and water. We purchased bags of clay from a local rockery, and the straw and sand from the hardware store. Ratios and how-tos. For these supplies, we spent around ~$250. The first layer of cob was put down and a shallow trench was created, which we filled with bottles and perlite for insulation. Because of a fairly rainy winter in Oakland, we had been able to spend a good amount of weekends imbibing some craft brewskis and saving the bottles for the oven.
Once the insulation was added and first cob surface was sufficiently dry, more cob was put on top to create a good level base on which to put the fire bricks that would be the cooking surface. We found the fire bricks used at Oakland Landscape and Supply. The folks at OLS are super nice (it’s now my go-to place for rocks and such) and we got a great deal on the used bricks. They came from a local bakery that recently re-did their ovens. The total was < $50. Joel laid out the firebricks after the level cob floor had fully dried.
Next, Joel and Abe fashioned an opening for the oven out of a shaped piece of leftover particle board (Abe is a woodworker and had a bunch of scraps). They shaped a cob opening around it and around a galvanized pipe for the chimney. Using sand, they built a dome,sized as big as what was to be interior, and covered that with newspaper. When the cob opening was completely dried, the sand dome was covered with cob. When the entire oven was dried, Joel shoveled out all the sand from the newly finished oven.
At this point, the oven was usable, but I wanted to prettify it by making a mosaic. I purchased a bunch of broken Mexican tiles (~40 lbs of tiles) from Tierra Y Fuego. The cost of this was ~$100. Applying the tile was much more challenging than I anticipated. In hindsight, instead of placing the tile directly on the wet cob, I would have waited for the cob to dry and applied a layer of thinset mortar to place the tile on. Since I didn’t do that, when it came to grout the mosaic, I struggled with shifty tiles.
In the end, Joel and I are psyched about our yard, the future, and possibilities.