I wanted to share the process of building this oven because whether you are going to have one built, planning to build one yourself or if you just feel like reading drivel, wood fired oven’s (WFO) are gaining popularity every year. Everyone agrees that they have many qualities that make them enjoyable and if you love to entertain, a WFO can’t be beat.
There are many ways to go about this successfully. The following walk-through is just the way mine was done. I wrote another post halfway and stopped because there is too much detailed information to cover. I have to abbreviate the process but if there is any part that isn’t clear to you, feel free to ask questions in the comment section or the forum.
It’s worth mentioning that there are a couple of things you should know and consider before construction starts, for example thermal mass and expectations. I will talk about them in another post immediately following this series. But to start off, let’s back up a bit……
Almost immediately after finishing Ed J’s WFO, I began making plans to build one at my own home. I definitely wanted to build the oven itself this time so that’s were I began my planning. EDIT: THE OVEN BUILT HERE IS THE POMPEII DESIGN POPULARIZED BY FORNO BRAVO. The oven plan that I used is from them and it is designed to help anyone build a functioning oven. I didn’t follow it to the letter, but not because it wasn’t good… but because I wanted to implement some other ideas I had.
There are a few different brick oven shapes that are out there. The two shapes I considered were a dome and a barrel vault. The dome looks like an igloo and a barrel vault has straight sides with an arched ceiling. One type doesn’t have any huge advantages over the other …at least, not in performance. It is something of a personal preference when deciding between the two. I chose to build a hemispherical dome (high,Tuscan) mostly because I had never done anything like that from hearth height. The beehive ovens I worked on were not complete builds, and I wanted something that replicated them. If you are not a mason or have limited experience setting masonry units, then a barrel vault might a better choice because it is slightly easier to build. But don’t let lack of experience discourage you if a dome is what you want…its a fairly simple process of actually setting them.
With the oven shape decided, and a spot picked out in the yard, it was time to excavate. I don’t have any pictures documenting this stage….sorry, it’s something I’m working on. My house in CT had outstanding topsoil and it was about 18″ thick! I was told it was pastureland at one time…great for my wife the gardener, but not for me. All my neighbors have stone but I didn’t..go figure! So now I had a small problem. The trouble with a lot of topsoil is that now I had to dig deep to get to sub-soil. This is because you need a solid footing and topsoil doesn’t qualify for that. Fortunately for me, my Dad was up in CT during this part and so he was running the backhoe while I directed and fine tuned the hole for the footing. We ended up with a 3′ deep hole to get down to hard-pan subsoil……over-kill yes, but I didn’t want the leaning oven of CT and all that topsoil and clay made me cautious. After compacting the floor, we then built up about 12″ of the footing with broken flagstone and concrete pieces from a sidewalk laid flat and tight. All the gaps were filled with crushed stone to prevent shifting and this would be a nice solid footing for the concrete.
After we built up the base and the forms for the sides, I ordered the concrete for the following day. Since the oven was in the back of the house and there was no access, we had to shuttle concrete from the truck to the form with our backhoe loader bucket by bucket. It went fast and before you know it, I had a footing! This was done in the spring of 2007 and since we were expecting our little boy in July, it was a chance for the slab to cure and settle without additional weight.
Fast forward to summer 2008. The slab was still perfectly level with no cracking..Yes!! It was time to start building the stand.
This is the block structure that supports the oven slab, oven, walls and roof. When we built Ed’s oven stand, we mortared the block courses. In the oven plans from FB, it showed a stand with only the base course mortared to the slab, and the rest were dry-laid then core filled. I hate doing block work so if it worked for them and that method speeds this part up, great! This is about the time I started taking pictures. Dry stacking the block worked fine, but expect imperfections in the block to throw off the level here and there. use a grinder ( use ppe and be careful ) or a brick rub to take them down.
Here you see the footing and the beginnings of the block course.
The first slab was made with a bagged concrete mix rated for 5000 psi after 28 days.
The next step is the insulation layer for the floor. This is critical!! Insulation under and around all the firebrick makes your oven efficient, and if you omit it you will struggle with balanced heating and it will be difficult to get the oven up to temperature. Insulation is what keeps the heat ( heat soaking) in your masonry (Thermal mass ). For the floor insulation I use a mix that has vermiculite in it. You can use perlite instead or ceramic board insulation, which can be found online. I like using vermicrete or perlcrete for two reasons: its inexpensive and it works. My ratio for the floor is 8-10: 1 vermiculite: portland cement. Gently mix so you don’t break up the flakes or perlite….you want a nice airy mix. It should look something like oatmeal when you are done. I only used the insulating mix (Vermicrete) under the floor. The outer edges are the 5000# mix because this is where the sill of my walls will lay, and I wanted a solid footing.
Next up in pt 2….. the oven floor, dome and vent.