42” Corner Build in the Shadow of Mount Nittany

[Giovanni Rossi]

Hello all,

Finally starting my build thread. I wanted to get this done while the snowy weather had construction on pause but many things conspired against me the last 4 months. I am ready to insulate the dome once I get the winter tarp removed and placed back on the canopy frame. The answers to most of my questions were already on the Forum. A few more were acquired by commenting on ongoing builds or via private messaging. I still have some unknowns about the final dome cladding and roof structure that I hope to resolved using this thread.

First, and most importantly, I need to thank all the contributors to this Forum. I’ve wanted to build an oven for years and finally got things rolling after retiring during the COVID lockdowns. Friends I talked to during the initial planning stages were all eager to help. However, it became clear right away that they all were thinking…weekend project. I certainly knew what I wanted to do was much more involved than that as I had knowledge of the process from a buddy who had built a barrel oven a few years back and from limited reading. Since then, I have read every post from 2021 on and numerous older ones as I searched for specific topics. There isn’t any question I needed the knowledge available on this site and recommend to anyone looking to build an oven to use this resource.

Much of what I will document will be familiar elements that can be recognized by anyone who spends time reading this Forum. While I’m sure I’ll miss giving proper credit to some, I’ll do my best. First, thanks to Mike Stansbury (a fellow neighborhood baker) for welcoming me to the Forum in 2021, kindling my interest in a corner build and providing guidance on posting.
I’m a long-time bread baker and pizza maker. I typically bake bread from Oct to April to avoid heating the house in the summer. The main reason for building the oven was to be able to bake year-round.

I have a fair amount of woodworking and construction experience but the required masonry skills were not in my toolbox. I don’t believe my experience uncovered any fantastic new building techniques; but, I’ll try to make this thread relevant to those considering taking on this type of project by showing my thought process, challenges and lessons learned.

I currently bake pizza (and the occasional loaf) in a firebrick/baking stone set up in my grill. I’ll add a couple of pictures about that to practice that aspect of posting.

Giovanni (John)

[JRPizza]

Looking forward to your thread. Even though I have a WFO I typically bake a loaf of bread a week in my gas grill using a glass top aluminum pot that acts like a dutch oven. Keeps the house cool and firing up the oven for a single loaf is a waste of wood. Even when we are firing the oven it's easier to use the grill timing wise as I always have trouble having the dough ready when the oven is

[SableSprings]

Great to see you're back in the build game! Amazing how so many people still think they'll throw together a WFO as a weekend project... I''m honored to be mentioned here as a positive influence in your decision to build an oven. My bread baking has been slowed considerably as I'm returning to brewing beer and have been working on expanding my bake/prep room into a bake & brew room with a cooler section for supplies. Life is never simple but certainly can be fun!

As JR already noted, we're looking forward to your build.

[Giovanni Rossi]

The first order of business was to decide on location. I envy builders who had multiple options. My backyard is bordered by Eastern Hemlocks so the only safe from tree root issues site was right in the middle of my small yard. That location was not ideal and was farther from my house than I wanted.
My preferred site was bordering a stone patio. I reviewed the local building codes and took some measurements and submitted a building permit. While waiting for approval I did some exploratory digging. There is a hemlock just out of the picture to the left and will be about 4’ from the corner of the stand. The disturbed area in the first pic is where I salvaged some stone from an old dry-laid wall to rebuild one in the front of my house in 2021. This proved to be a problem later.

The decision from the local authority was that my permit was neither approved nor denied but that a permit wasn’t needed for this type of construction…so let the digging begin! I made a pile of topsoil for use later and started a second when I hit clay. I really agonized over the depth of the hole. Convention for this latitude is to dig 40-48” to get below the frost line. Opinion on the Forum as well as discussions with local contractors left me 50:50 on the decision. I just decided to try to go that deep to be safe. I took some inspiration from Bean(Animal)’s Pittsburgh build. Similar latitude similar soil composition and site topography. I then ran into the subterranean part of the old wall. It was just junk rock, large and small and some red brick from the house construction (1937). This turned out to be good and bad. It added hours to my excavation but seemed to stop the hemlock from growing large roots into my site. I found some roots at one side of my site that I wanted to try to save so I had to shift closer to the stone steps.

[Giovanni Rossi]

The slope of my yard at the site made digging difficult. The depth along with the distance I had to toss the clay made the process awkward at best. I finally resorted to using a pry bar to dig and a post hole digger to drop the soil on the “island” and then shovel and toss from there. I hit bedrock at ~ 3’ in the front and 7’ in the back. I know I work slower than I used to but that was a tough 24 hrs of excavation.

The canopy I ordered arrived damaged and it took weeks to resolve the issue. There was a lot of rain during this time so a lot of tarping in between work sessions. One positive was that the tarp failed after a particularly heavy rain and even with all the clay soil the trench drained. I had to tarp the clay island all the time because once it got wet it wouldn’t dry and was impossible to stand on to work.

I had some leftover rebar from another project so I drilled into the rock and epoxied it for good measure. This is one of those points in the project when I was probably out of my mind.

A buddy convinced me to mix the concrete for the footing and lent me his mixer. This is one of those times I wish I owned a truck. Only one of my friends does but, heaven forbid, we scratch it. I decided to save a buck and rent one from the big box store. Well, its weight-limit sensor was damaged and I ended up making 4 trips to get one load of CMUs, concrete mix and rebar. Went over the rental time limit so they gave me some gratis rebar to make up for it. All in all should have just had the supplies delivered.

Had a lot of delays waiting for dry days to work. Daughter fashioned a ramp to guide the flow from the mixer. This is one time the slope of the site helped. Footing complete. All my previous experience with concrete work was small batch pours and mortar using a hoe and mortar box. Cant’s say I’m a fan of using a mixer for that much concrete.

[Giovanni Rossi]

The foundation work was next. Had to make sure the finished height of the slab on grade was a couple inches higher than the stone patio but had to leave room at the corner (oven front) to extend the patio.
Laid 2 courses of CMUs. My only exposure to this process was in middle school laboring for my dad while he laid the foundation for our home. It didn’t take long to realize I’m not very good at it. I think I could improve with more practice.

Still didn’t have the canopy. It was a brutally hot day. Just couldn’t get the mortar consistency right. Finally had my wife set up a beach umbrella to shade the wheelbarrow to get a little longer working time with the mortar.

[Giovanni Rossi]

Current project is building raised-bed garden plots for my wife. It’s a rainy day so I’ll keep going with the posts.

Next up: slab on grade.
While I had easy access, I dug out for a couple of Sonotubes in case I decided to add anchors for posts later. I trimmed the clay pad and filled the space with drainage stone and hand compacted it. Drilled ½” holes in the footing to receive the rebar through the CMUs. Cut and bent the rebar.

Had to construct a temporary retaining wall because the soil was drying out from the hot weather. Set the forms for the slab and added braces for the top and bottom of the tubes. Set the rebar, tied up the grid and filled those CMU cores with concrete to hold the grid in place. Knowing the suspended slab was in the future, I decided to buy rebar ties and a twister tool…game changer.

[Giovanni Rossi]

Time to pour the slab. The last thing was to tuck in and unroll some heavy-duty plastic under the rebar for a moisture barrier.

After our experience transporting supplies and the time to mix all those bags of concrete mix, I decided to check into Redi-mix delivery. Contrary to what a contractor working at my house told me about the cost of small loads, I found that I could get a yd delivered for a little more than the cost of truck rental and bagged mix. I could get a consistent mix at 5000 psi and the slump I wanted (4 for this pour).

This meant I would need a wheelbarrow crew to get the mix to the back yard. The picture doesn’t do it justice, but that’s about a 30^o rise to the sidewalk and then 25^o for 50’ to the top of the driveway then another 100’ to the site. Wife, son, daughter, and a neighbor shared the duty. They were an amazing team and finished in about 30 minutes.

Thinking we would dump half of the load from the top of site and the rest from below, we built a ramp to get down to the patio and repurposed the chute from the footing pour.
It turned out to be easier to just pour from above over the temporary retaining wall. That worked well other than me being on the receiving end to shovel the concrete into place. Needless to say, I needed hosed down afterward.

The quantity worked out very well. Ended up with all the CMU cores filled, a 6” slab and the tubes filled and had about 2x 5 gal buckets remaining. Worked it with a bull float. Once it set up a bit, I troweled it smooth, popped the corner form and worked a bullnose edge to dress it up. Covered the slab with wet burlap and plastic sheeting. Allowed it to wet cure for 3 wks while I worked on the stand design.

[Giovanni Rossi]

Really wanted to try mortaring the stand but couldn’t risk another headache. Took inspiration from Russell (UtahBehiver) for my stand design. I liked the clean lines and the lintel integrated with the suspended slab. It also gave good support under the dome. I had purchased an angle grinder to help with rebuilding a dry-laid stone wall in 2021. It made short work of the cuts in the CMUs. I believe it has become my favorite power tool!

Added some plywood with 2x2 legs to support the Durock board. It probably wasn’t necessary for such small gaps.

I planned to coat the slab under the oven with Redgard as Mongo did. Knew I was going to have a lot left over so I coated the two sides of the stand that will be below grade. Definitely needed to put support under the center.

[Giovanni Rossi]

An earlier post showed me cutting rebar with my trusty angle grinder. Normally I would lay the bars on sawhorses or at least on the nearby stone steps, but I found myself getting lazy and just cutting wherever to save steps. I had just finished cutting a few pieces. And felt some warmth on my hip. My first thought was that I was overheating the grinder…after a few seconds I realized the sparks had set my shirt on fire! Lesson learned without any bodily injury.

I struggled with figuring out the best way to form up the cantilevered edge on all sides of the suspended slab. I was going to do it on only the three sides at the front, but realized I needed a little more surface area at the back of the dome I planned. After a couple PMs with Mongo I was back on track!

[JRPizza]

Save the fire for your oven
Seriously, glad you noticed before it was stop, drop, and roll time!

[Giovanni Rossi]

You know it JR!

Taking a cue from Barry (Baza) we decided to place a time capsule in the build. So, before the ½” Durock was placed we lifted the support on the left side and deposited the capsule in that cavity. My daughter took on this project so she put whatever relevant stuff she could think of. This included local and national current events (lots to work with given politics, climate issues and COVID), N-95 mask, coins, family news and pics, house and oven plans, our pizza party menu and our dough and sauce recipes. I hadn’t noticed before that she even put in a shout-out to the FB Forum on one of the Post-it notes! It’s pretty secure in its concrete chamber. Hopefully whoever opens it will find it interesting and/or have a few laughs.

[SableSprings]

John, I hope it's not too late...before you pour that top hearth piece put some small wedges under the center support posts. The weight of the cement pushes down so much that it will be pretty difficult to remove them when you "unveil" your pour. It was shocking to me how much time I spent trying to knock my support posts out after my hearth had cured enough to pull the forms. Everything else is looking great!

Are you going to put any little bronze plate on the side of the cavity holding the time capsule?

[Giovanni Rossi]

Thanks Mike, I'm just catching up to the present with this thread. I'll be insulating the dome as soon as I get the winter tarp off my site.

I'm glad you asked about the wedges for prospective builders who may read this in the future. I actually had wedges ready to go (more good Forum info from my research) but that 2x4 frame I made fit so well that I would have had to re-cut all the verticals. So, I just decided to use a reciprocating saw to remove it after the slab cured. And yes, you are right, I had to saw a wedge on each one and finish the job with a hatchet.

Indeed, we are planning a plate to mark the spot so they will be gentle with the demo when the time comes!

[Giovanni Rossi]

Time to finish the prep for the last concrete pour. With the time capsule in place the Durock board could be put back in position.

Forgot to add that once I had the stand placement determined and had two courses in place, I drilled into the slab-on-grade to receive the ½” rebar that would track through the cores and be bent into the suspended slab. I grouted the cores to hold the rebar in place. Still had left over bagged concrete mix I couldn’t return (long story) so I just filled the rest of the cores to about the halfway point on the top course.

With the forms in place, I could make sure the horizontal rebar stayed 3” from the edge of the pour. Took another page from Russel’s (Utahbeehiver) playbook and cut a channel in the top block at each end of the lintel. Used a #6 epoxy coated rebar and tied it into the vertical bars. I drilled through some 1 ½ “ PVC pipe then crosscut through the hole to make some rebar chairs.