42" build in McPherson KS

[slschoming]

My wife and I lived in Italy for a year when we were newlyweds and we fell in love with wood fired ovens. Now we're back in KS and have three kids that are in love with wood-fired pizza. I've been dreaming about starting this build for the past 10 years, and am hoping to finally make it happen. I have never done any masonry or concrete work, but I'm hoping that this project will teach me everything that I need to know. Here are a few pictures of my slab which we poured yesterday. I am hoping to start the block work sometime next week. I've read the Pompeii plans multiple times, and have been reading about other things like weep holes and homebrew on the forums. I know I am bound to make some mistakes along the way, but very much appreciate all the documentation that I've been reading about newbie mistakes and things that have changed since the Pompeii plans were put together.

Here are a few details about my project.

1. I plan to make a 36" corner build over a 60" x 60" slab, with a 36" x 72" prepping station adjacent to the hearth.
2. My hearth will have a little bit of overhang so I have a little more room to build the dome.
3. I am hoping to maintain an igloo with no roof overhead in a KS climate that experiences all the seasons.
4. I intend to learn a lot, have some fun, and meet some neighbors in the process.

[mk e]

Looks like you're off to a great start.....even if the plans are now a bit hard to read

I've learned that everything takes way longer than it seems like it should and that's just the way it is so think well before mixing a new batch of anything late in the day.

[UtahBeehiver]

Yes the FB eplans are little outdated but a good base line. Peruse the blog for the latest innovations and improvements or ask away. It will be a little tough to work on the back side of the oven being so close to the fence. You may have to temp. remove the slats to work back there. Be sure to query the blog with any questions, most everyone wants the builder to be successful and avoid learned errors. Easier to correct on paper than once the bricks are laid.

[slschoming]

mk e, I definitely agree. I already had the concrete truck show up an hour and a half late so my father-in-law who came to help had to leave me for a bit to take care of a few things. Then, the concrete truck came up short on concrete. Luckily, a neighbor (with much concrete experience) came out to see what was going on and offered to start finishing my concrete while I ran to buy 4 bags of quikcrete. By the time I got home, my father-in-law had arrived and was working with my neighbor. (I plan to pay them in pizza later....) With my 4 bags we had enough concrete to fill in the forms, but the last wheelbarrows full were pretty wet later into the day than I hoped. I had to leave for an hour while that was still sopping wet, but luckily it was still workable when I returned at sunset.

Utah, I removed an 8 foot section of my fence to pour the slab, and I should be able to remove the other side of that corner pretty easily as well when I am working on the dome. I may actually end up building a temp fence further down to keep my dog in, then I could keep the fence down until I finish up. I have three small kids so I find small gaps of time here and there to work on projects and don't want to have to spend half that time taking down fence and putting it back up.

I plan to use FB board (on top of an upsidedown sheet of tiles leading to weep holes so I don't absorb water) and FB insulation blanket. around my dome. Then I hope to do either a waterproof stucco outer dome or a brick dome similar to cobblerdave's as my outer layer. I have been reading a lot about water getting into the insulation and we generally have cold winters with ice storms and wet springs so I am pretty nervous about waterproofing, but I would really like to be able to maintain an igloo with no roof.

I do have a couple questions about the dome (which I'm nowhere near ready to start yet anyway):

The part of the slab that will be directly below the oven is a 60" x 60" square, which is a little smaller than what I generally see in the plans and in other builds, but I was hoping to overhang my hearth by about 6 inches from the cinder block walls. Does that sound reasonable or am I already setting myself up for failure? If so I could always reduce the inner diameter by a few inches..

This is probably a dumb question, but I would rather ask it than do it wrong.... When I start the dome, I imagine it will be a multiple day process. I plan to use homebrew mortar for the joints. Can I just mix up enough homebrew for the day, lay a days worth of chains, and cover it up and come back to it a later day? or do I need to do anything special when I call it a day? Do you do any curing fires before the dome is complete if you don't get it completed in a day?

[UtahBeehiver]

I dry mixed my homebrew in a 5 gallon Homer bucket and then made small batches of mortar, ie a gallon bucket of so. Any excess or flashed mortar used on outside of previously layed brick so not to waste. If you mix a days worth it will flash too quickly. Laying the bricks for the dome require a little fitting and adjustment so smaller batches mixed by hand seem to work better.

There have been some builds with fairly large overhands from the CMU base. A bulk of the weight is at the dome wall area. If you correctly rebar the hearth, IMHO, you should be okay.

[slschoming]

Thanks for the reply, and thanks for the mixing advice. The more I read and the more questions I ask, the more confident I feel!

I imagine that only the weight of part of my arch/opening would be out on the overhang.

I am planning to pour the hearth and countertop for the prepping area all at the same time (same depth). Should I be scoring a contraction joint between the two like I did in the slab? Or should I not even be pouring them together in the first place? Any advice is welcome!

[slschoming]

Hey UtahBeehiver, if I do a 4-inch vermi- or pericrete layer instead of using FB board under my fire brick floor do I need to worry about weep holes and water issues? The more I read the more I think I'm going to need a roof overhead to keep water out of my dome insulation.

[UtahBeehiver]

An enclosure or roof over the igloo will certainly minimizes water getting in via the dome. However, there are many exposed igloos that have weathered the storm, you just need to weatherproof as best as possible. IHMO you still need weep holes with p/vcrete for any water the gets in can have a egress out. P/Vcrete is a very porous structure and lots of place for water to gather. In addition water on the hearth could wick up as well. Another water source is the entry way, some builders have made what I call a storm door to project the vent area from water getting in and to the insulation, I know David S of Australia suggest a crown in the middle of the hearth sloping out to the edges with weep holes. You could do this then pour the top of p/vcrete level for accepting the firebricks.

[slschoming]

Thanks UtahBeehiver. So if I do the david s crown method, the weep holes would only be through the structural slab and the p/vcrete would be a solid pour with no holes, correct?

[UtahBeehiver]

Yes, only in the structural hearth. Some builder place a piece of wire mesh over the bottom of the hole to keep bugs out. You only need 2-3 weep holes.

[slschoming]

Trying to visualize before I actually dry stack. I'm going to have to cut some blocks and level the bottom row before I actually get going on this.

[Gulf]

How far out of level is it?

[slschoming]

Gulf hardly at all. There seems to be one little hump in the slab that makes the bottom row slope just a little bit in one spot. When I said that I was going to level the bottom row, I meant that I was going to put down a layer of mortar under the very bottom row only, so I could get it nice and even. No mortar between the blocks, just under the very bottom row to ensure a very level start. after stacking I plan to fill some specific cores, and then apply a layer of colored quikwall around the whole thing. Do you think I could get away with just stacking without adding the mortar under the bottom?

[cobblerdave]

Gday
Get out those blocks and have a play. Don't forget those things are built to have a Mortar joint to go around the corners so those blocks will have a 10 mm play.
A tape measure from back left to front right and from back right to front left ... if they are not the same.... time to move them around cause they aren't straight.
when you satisfied your on the right track Mortar them down.
Dry stack with washers etc to keep it on line.
Sloppy concrete poured in the corners then ever secound block hole, the others fill with empty concrete bags beer bottles etc.
If your a bit off with with the levels don't worry you'll catch that with your top slab.
enjoy the journey!
regards Dave

[Gulf]

Do you think I could get away with just stacking without adding the mortar under the bottom?

I think Dave has just about covered it. Just dry stack and then fill at least every other core.

I'm not sure what you meant by "cut some blocks" ? It is easier to lay out the footprint of the stand for whole and half blocks.