36" (900mm) Pompei build in central Sweden

[icrackracquets]

This post has been a long time coming, so let's do it. I saw some plans for a quick barrel oven build at the end of summer last year. I really wanted to build it. Because it's such a permanent structure I started reading more about it which led me to this forum/website. Once here I quickly realized that not only was the design for the original oven I found quite horrible, but also that if I wanted a more multipurpose oven that would last and work well then I'd need to switch to an igloo. So I spent pretty much the entire winter looking up the tools and materials I would need to do the job. Let me tell you, that was a long and tedious process. I'm an american who moved to Sweden a few years ago and I'm about 80-90% fluent in the language. But when we're talking about specific/specialized building products and equipment that makes it quite difficult to get the right translations for materials.

Materials
Everything seemed to be more expensive here compared to the other builds I read about (primarily american). Bricks were the worst. Australians I feel your pain. Firebricks, when ordered online, cost about $4.50 each. Or could go to a hardware store and buy them in person for $8 each. Needless to say I spent a large amount of the winter and spring looking for 'used' or leftover firebricks on facebook marketplace or blocket (rough equivalent to craigslist here). The standard brick dimension is 230x114x64.

I found 60 'valvsten' bricks for about $2.50 each. This means they were already precut for a certain diameter arch so they're dimensions were 230x114x59-69. This caused some small problems later.

Next I found 123 bricks also for $2.00 each. Now these were stacked outside on a pallet. Once I got there it turned out to be 6 different dimension bricks. 92@ 250x120x60, 18@ 200x95x55, 8@ 225x110x64, 2@ 245x120x75, 2@ 295x145x75, 1@225x110x40. I figured this was good enough so I went with it. The 92 bricks I used for the dome/arch and the rest I cut down to workable sizes for the floor. So my oven floor is a bit crazy. Pictures later. However, those 92 bricks caused me a lot of problems. I realize now that these were obviously hand cast in molds and hand cut with wire. This means that the all bricks are slightly uneven, cupped, warped, or slightly different thicknesses. As a someone who really strives for accuracy this was perturbing. To top this off all of them had been left outside stacked on top of eachother for so long that there was a large amount of mold on over half of them. I picked them up in winter so this was not readily apparent until spring when my garage then smelled strongly of mold. I ended up putting most them on a charcoal grill about 5 at a time to kill all the mold. Still didn't completely succeed.
I realize this sounds a little whiny, sorry about that. I fully realize that I did this to myself

After that the secondhand firebrick market dried up so I ended up needing to buy 19 new firebricks. After a mistake with my order I ended up getting an extra 19 delivered by accident which they then said I could keep, so that was a nice bonus. These extra bricks ended up being just enough to build my entry vault.

I had originally thought to do concrete sacks to make the foundation and hearth slab easier. This turned out to be financially restrictive. I got rocks and sand from my local recycling center, bought cement/rebar, borrowed a drum mixer from a neighbor and poured the foundation and slab that way. I'm a structural engineer by trade so I was able to calculate the reinforcement I needed.

Ceramic insulation, both hard and soft, seemed to be about on par with the rest of the posts in terms of price so that was nice. Basically only one online supplier though.

I used the homebrew for mortar for the dome. 3-1-1-1. I had to really water it down so that it wouldn't suck into the (soaked) bricks and dry out immediately. Fireclay was hard to source online without incredibly high shipping rates. Ended up buying some from some random small company that installs fireplaces. I found one single store that carried the lime (Weber Släkt Murkalk e).

Tools
While I learned a lot from this forum and there is no way I could have completed this project without the forum, there are some drawbacks.
1. Not everyone has access to Harbor Freight. The answer cannot always be 'just run down to harbor freight'.
2. Not everyone knows how to weld/has welding tools/knows someone who knows how to weld (this is mostly just in relation to the indispensible tool)

Now tools in Sweden are incredibly expensive. Trying to find a tile/brick saw took a lot of effort. Your standard sliding wet saw that everyone buys for $200 dollars at harbor freight? About $1500 here. I looked into tile saws but there are two options. Your standard small blade table tile saw which can be found for about $40 (requiring at least 2 cuts to get through the brick). And then tile saws with larger blades starting at $400. There is quite a substantial price jump just for the larger blade. Then I tried to just find a masonry blade for a cheap miter saw. Unable to find a masonry blade small enough. And to get a miter saw with a larger blade was also prohibitively expensive. Eventually I bought a metal chop saw (just up and down straight cuts, no angling options) with a big blade for $150 and slapped a masonry blade on there. Dear god this saw was loud. And yes, so much dust. Many double shower days because of all the dust.

I spent a long time trying to find the right indispensible tool design and didn't really find anything on the forum. Too many designs included welding. I ended up bolting an angle to a threaded rod with locknuts and coupling nuts. These I connected to the plywood floor form with another coupling nut, a caribiner, and a loop screwed to the plywood. In retrospect I did not like this design. Try to make a fixed length one without a break instead.

Angle grinder was on par with price and was easy to find. If you're like me, never really used an angle grinder before, and think you can make accurate cuts with it. You are mistaken. I was bad at using this tool

[icrackracquets]

Foundation
As I've said before, I am a structural engineer. I know how concrete works, I know how to calculate it's strength, I know how to calculate the right amount of rebar. I am not a construction worker. Casting this was difficult. I did it alone with a drum mixer. It took 7 bags of cement, 500kg of rocks, 300kg of sand. I am a reasonably in shape person and measuring and pouring this much material destroyed me. I was very tired afterwards.

Stand
I built the stand out of Lecablock as it's known in Sweden. These are the standard for light masonry here as opposed to CMU. Apparently these are also named Leca block in America too although I don't ever remember seeing them in any hardware store. I spent awhile trying to figure out how to anchor the units to the foundation below as there are no holes, they're just solid rectangles. In the end everything I read said that it wasn't really necessary. So the block is just sitting on top of the foundation relying on weight and friction to hold it in place.

Slab
We remodeled our kitchen about two years ago and I saved all the shelf boards and planks that I could. Thank god I did that because this saved me a lot in forms for the hearth slab. The form is just a bunch of square sections screwed together underneath with spare wood. Now to the sketchy unsafe part. I still had the drum mixer but I remembered how physically exhausting casting the foundation was. I couldn't figure out how to pour the elevated hearth slab. Ordering concrete with a truck was out of the question for only 0.25 cubic meters of concrete. I don't think I could have the energy to pour the concrete from the drum to a wheelbarrow and then shovel it up to the slab form. I thought about building a ramp to push the wheelbarrow up but that also sounded exhausting. So my solution was to build a stand out of scrap wood that the entire drum mixer could stand on in order to pour directly into the slab form. This looked sketchy as hell, but it worked and saved a lot of effort.

[icrackracquets]

More photos

[david s]

The dust created from a brick saw or angle grinder if cutting dry creates a lot of dust. This dust contains crystalline silica which is dangerous to inhale for the operator, their family and neighbours. You should research the topic. Wet cutting can reduce the dust by over 90%. Just soaking the bricks only reduces the dust by a tiny amount, it needs to be a dedicated water feed.

https://cancer.org.au/cancer-informa...er/silica-dust

To clean up the mould on the bricks which may prevent getting a decent bond to the mortar, your angle grinder fitted with a coarse flap disc will do a good job, but will not create the dangerous dust like cutting.

If you have researched this forum you may have come across underfloor weep holes which greatly assist in the removal of moisture. Try going to google and search "forno bravo weeep holes". someone else here may chime in to provide some appropriate links. They are better to cast in when poring the supporting slab, but can be drilled into the green, cured or dry slab. But you will have to work out wher the steel mesh is to avoid hitting it. It is a worthwhile job to do now, before proceeding. The underfloor moisture is where the accumulation mainly occurs and is also the position that is the hardest to eliminate.

[icrackracquets]

I'm currently at the curing stage. I've just been lazy in posting to the forum. More progress on the build is coming soon. I did one large weep hole cast into the slab but the concrete ended up sloped upwards towards the weep hole on all sides. So I ended up drilling two weep holes into the slab.

The ship for wet cutting has sailed. Again the cost was in the thousands of dollars. So it ended up being 'dry' cutting with soaked bricks and a mask.

[icrackracquets]

As I moved onward to the actual making of the dome I became incredibly bad at taking pictures. I always meant to and never did. I could work 1-2 hours during the day while my wife watched the kids and 2 hours at night after the kids went to sleep. So I was always rushing to get started and tired when I was done. So I have very few pictures of the making of the actual dome which is a shame.

I'm not very good at casting concrete. My hearth slab was not as neat and clean and flat as I had hoped it would be. I read a post about broken up tiles underneath the calcium silicate board to raise it off of the slab and I thought that sounded like a good idea so I went with it. Because my slab wasn't super flat and the silicate board I got was not great quality (I sent some complaining e-mails) it was difficult to get these level. I ended up using a good amount of sand around the tiles in order to even out the silicate boards. When I went to put the floor in these still weren't even enough so I needed to also do the sand/fireclay mix underneath the floor bricks. I am very tired of leveling things.

I read one post, from Sweden actually, that made their own under oven insulation out of leca balls. The same thing as the leca block I used to support the hearth slab. I thought this sounded like a good idea to keep cost down however there wasn't any after oven checkup so I don't know how well they performed. I ordered silicate board for underneath the dome and used leca balls underneath the entry vault.

I mortared the half soldier course first, cut the floor bricks using a template, then installed the floor after the half soldier course. If I were to do it again I would have reversed this. Installing the floor bricks after the half soldiers necessitated som extra shaving/cutting in order to get them to fit. You can see my frankenstein floor in the pictures that I did in order to use as many of the secondhand bricks as I could.

[nlinva]

That is some precision cutting on your oven floor! Especially the piece towards the bottom right that looks like a letter L!

[UtahBeehiver]

Thanks for posting, repurposing material is a passion of Gulf (also a moderator) and myself so it was great to see you root around for you fire bricks. Great work and looking forward to seeing the rest of the project pictures. These prove invaluable to future builders.

[icrackracquets]

Alright. Next was casting the dome up on the half soldier course. As I said, I've never done masonry before and my half soldiers were kind of dirty. It was only after this course that I read more about it and realized I needed a damp sponge to wipe up afterwards. That made things much nicer.

I used the pompeii dome spreadsheet that you can find on this forum very easily. I looked through it and modified it based on my bricks. This is because I had multiple different sizes and types of bricks. Then, because I work as an engineer and have easy access to modelling programs like revit, I drew up many detailed to scale drawings of how the entire oven should look, how to cut each course of bricks, etc. I tried to be as accurate as possible.

I used a cutting jig I've seen on posts here before. Two OSB boards screwed together with hinges. See my pictures below.

I said I made very detailed drawings. Well this doesn't really do much when:
1. You've never done masonry before
2. You've never cut bricks before
3. Your saw doesn't make cuts with the accuracy that you calculated
4. You have unpredictable sizes of mortart joints
5. Your bricks aren't completely square and even.

So even though I went through a lot of time and planning to make as detailed drawings as possible, that's simply not how it turned out. This bothered me a lot as I was building it, but now after it's done and I'm curing, I'm just glad it's done and that it works (so far).
So if you're like me and you want everything you build to be close to perfect, it's hard but you have to just let it go. I know. It's hard.

I used leftover pieces as shims in the back as almost everyone suggests. Even though my arch is completed and stable, I still don't know the best way to cut the bricks for a good transition between arch and dome. Mine required lots of mortar and awkwardly cut bricks. After cutting the soldier course I was skeptical I would have enough sand/dust from cutting to make enough mortar so I bought some fine sand to make up the difference. This ended up not being necessary. Once you're making three cuts per brick you get enough sand.

[icrackracquets]

It took 3 weeks of working after the kids went to sleep every single night and I got the dome finished. Then just when you think you're done and tired of doing masonry and cutting bricks, then comes the entry vault and the chimney support.
I found a post on here of someone who built one in kentucky and he posted very nice detailed pictures of his entire process (unlike me). I thought his looked great so I followed the look of it very closely. It was this one: https://community.fornobravo.com/for...-kentucky-dome
Thank you very much Ken524. I wish I could have made my oven as seamlessly as your pictures make your process look.

Now Ken had a vault that was wider in the front and narrower in the back, a flared vault approach that I felt made the oven look very open and accessibly. I did build mine this way, but figuring out the cutting, brick orientation, and general installation issues made me regret it. I think mine looks good (not as good as Ken's) but I wish I'd saved myself some trouble and just gone with a straight entry vault.
I built some simple wood buttresses to brace the entry vault walls as I have it completely separated from the dome, by about 10mm. I have som fire cord in the gap to close the air gap.

I've now put on about half the dome insulation. I'm doing the 300, 350, 500, 600, 700 curing process and am currently at the 500F stage. I'm working from home so I'll be able to hold the temps for a number of hours.

I'm going to build an enclosure around the dome as I feel it's a more water/weather tight solution.

Now my posting has caught up to where I actually am in the process. I will return later to show pictures of the final firing, the insulation, and the enclosure. I encourage anyone, especially Swedes, to contact me with questions if they wish. I did a lot of research on this project and I think I could help especially with material/sourcing questions. With the actual construction I'm skeptical you would want my advice.

[icrackracquets]

Well now I just looked at Toiletman 's latest posts and saw that he is also almost done. All that stuff I said about living with imperfections? Might as well forget that, follow whatever it is that toiletman did, and ignore me. Because that thing looks amazing

[Toiletman]

Well now I just looked at Toiletman 's latest posts and saw that he is also almost done. All that stuff I said about living with imperfections? Might as well forget that, follow whatever it is that toiletman did, and ignore me. Because that thing looks amazing

Wow, thanks for the compliments man! Although if I look at the concrete and plaster work that daidensacha is doing he's going to set a new quality example soon! RandyJ was building at the same time as me as well, but he raced past me. He built a very good looking oven, I'm especially jealous of the stone veneer... but at the moment he's already enjoying pizza's and Tomahawks, while I'm cutting granite in the blistering heat.

But as you already said: the chimney is probably going to be the most difficult thing to do, as well as being in plain sight .

[nlinva]

[QUOTE=icrackracquets;n460533]
I said I made very detailed drawings. Well this doesn't really do much when:
1. You've never done masonry before
2. You've never cut bricks before
3. Your saw doesn't make cuts with the accuracy that you calculated
4. You have unpredictable sizes of mortart joints


(I am trying to quote your post #9, but the preview doesn't show if it works).
I have had the exact same experience so far: make very precise calculations in a spreadsheet, and then realize that, especially for me as a novice, there is no way I can make cuts to anything remotely that kind of precision with my brick saw, let alone then mortar the bricks in place exactly as planned. Oh well, live and learn!

[JRPizza]

My inability to make the exact cuts is why I abandoned the spreadsheet. I used an adjustable tee bevel to eyeball the angle I needed to cut, and then transferred that angle to my saw. My joints were nice and tight on the interior and I just filled all my gaps around the outside and between bricks with home brew mortar. The only time I had to really try to set an accurate angle was when I tapered bricks for my arches.

[rsandler]

Similar experience, though I'd note there is some value in the spreadsheet calculator if you don't take it literally and try to cut a whole course (much less the whole dome) in one go and then expect everything to fit. It's useful to know for instance that the side angle will be about 5 degrees for all half bricks (on a 900mm/36" oven anyway), then shrink somewhat for 1/3 bricks. Similarly nice to know approximately what bevel you're aiming for on each course, even though the exact amount will require fiddling.