"Pompeii" corner WFBO project in Loei, Thailand

[UtahBeehiver]

Are you going to considered a tapered inner arch? If you are, then the arch form is too wide. Tapered inner arches take more time up front but saves a lot of time and fitting on the back end. Attached is a picture from Mr. Chipster showing how the IT helps you determine the angles and configurations of the arch bricks. This pic is similar to your arch but the concept is the same for full semi arches. It takes a full brick to work from, with the top center brick (top dead center aka TDC) being the longest dimension in the arch. Each brick is different so you cannot cut them all the same. You are halfway there by tapering the bricks for even mortar joints.

[TxGR]

While I am waiting on the ceramic fiber board, I worked on the arch forms based on the plans. I built the first form and then test fit it next to the brick. Turns out the brick is actually 23x 11.5x 6.4cm (not 23x 11x 7cm as I thought). Due to stacking, this becomes a big deal for all the plans. For starters, the arch frame is too high by ~1.5cm. So, we are now working on revising the arch plans to accommodate the actual measurements.

The silver lining is this motivated me to go back and look at pictures from previous builds. Looking at UtahBeehiver 's pictures, I reconsidered a few things:
- not building a plywood template
- having the flue inside the oven door
- the length/depth of the entry/opening

I hoped to avoid building a plywood template for the floor. That was a mistake and false economy. I built one and several issues were revealed and resolved. If I had started building based on what I already had, I would have wasted lots of time and materials.


I used a protractor with set holes to draw a "perfect" circle. I used the interior radius of the oven (55cm), thickness of the brick (11.5cm), and then added 2.5cm for "mistakes." This will be dimension of the ceramic fiber board. Of course, the plywood is smaller than the exterior dimensions, so I had to piece it together.

The hearth is 180x180cm. The tile was 90x 45cm, so the lines of the tile are the centerline of the hearth. Because of the entry, I always planned on moving the center of the oven back about 10cm toward the corner opposite the curve. I used chalk lines to triangulate center of hearth from corners and to draw oven center (80x 80cm measured from corner opposite the curve).

First big mistake: if you look at the picture above, you'll see the entries and template are off the edge. Solution: move it back to the proper line. I mistakenly lined up the template on the hearth centerline instead of oven centerline. The good news marking the chalk lines and lines on the template made centering the template very easy.

Second mistake: interior vs. exterior measurements. You might notice the entry bricks are on on top of the template. When I cut the entry extension I mistakenly used the interior dimensions.



This pic shows the template moved back properly and the pieces added back to the entry to support the entry/arch bricks.


Here is more of the dry fit with the template. Here I pushed back the entry bricks (explained below). You can't see it well here, but there is a 2cm reveal where a door would stop.

After looking at @UtahBeehiver's pictures, I decided to much more closely follow what others did. I'll encounter fewer issues and the issues I do encounter will be ones others probably faced.



To reduce the depth/length of the entry, I will cut back the arch bricks 7cm (inside brick) and angle them to conform to oven circumference. So, I will have to redo this form. I will move the flue to the outside arch.



This shows the 2cm reveal. The arch bricks with be cut at angles to achieve mortar joins of even thickness.


This top view just shows a different angle.

Dry fitting turned out to be very important and I am not done yet. I will do the same once I have the ceramic fiber board and brick floor roughed out, and again after I cut and level the brick floor. The next dry fit should include a new rear arch form and the completed front arch form. The fitting after that should include cut arch bricks.

Any comments and suggestions now are most welcome. They'll be more useful now than once I start mixing mortar.

[TxGR]

Here are some updated drawings with dimensions. Per UtahBeehiver 's recommendation, I will increase the offset of the bricks between the first and second set of entry bricks to 2cm on each side (and on top).



Here are brick cuts for the gateway/arch entry:




Also per UtahBeehiver 's recommendation, I will angle the top of the soldier bricks 18 degrees (outside edge 23cm, inside edge 21.25cm)...but then I will either need a mortar join line all the way through, or I need to reduce the angle cut to leave enough of an external gap for mortar. I might have to experiment with this a little.

I did realize today I grossly underestimated the amount of ceramic fiber board I will need. The base of the oven is 132cm x 161cm (dome plus entry). The ceramic fiber board here comes in boxes of 2 sheets, 90x60cm. So that won't cover it. I will have to figure out if I can get buy with another box or need two more boxes. This is 5cm thick.

Along those lines, I am thinking of shortening the entry by only using half bricks for the outer arch. Right now, per the plan, the entry is at least 46cm deep...that's pretty deep. If I use half bricks for the first arch, I can cut that back to 35cm -- still long, but it has to accommodate the 8" flue anyway. I built the inner arch form today. Tomorrow I will build the outer arch form to see how it will look.

I put down ceramic tile as a moisture barrier:


The red brick with the phony wood aluminum cabinet doors (ugh...not my choice), are a separate project. I contracted that out. This wing will have a sink and food prep area. We are holding on on the wing to right, where I plan to put a grill. We'll finish the oven first.

[TxGR]

I purchased some 90x45cm ceramic tile which will fit nicely on the 180x180cm hearth as a moisture barrier. On top of that I will put ceramic fiber board, then the oven floor firebricks.

In reading other posts/other threads, and UtahBeehiver suggested earlier, they added weep holes. The references I found were for a single weep hole drilled through the hearth base in the center. Other posts recommended 2-3, 3/8" to 1/2" in diameter. If I have a moisture barrier, is that still recommended? Based on one post on another thread, I believe the answer is yes. Then the weep holes should also be through the ceramic tile?

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Here are some pics of the "indispensable tool" we made. It's kind of crude, but allows for adjustment.



The center of the threaded rod is offset 3.5cm (half the width of the brick) from the edge and back of the "hand."


This is a better view of the "hand." The steel is 16 gauge and actually quite stout. We bent it in a press and I think it came out pretty good. Two nuts allow adjustment by about 5cm. With maximum extension, there is 55cm from the top hinge flap to the base of the hand. 55cm is the radius of the internal dimension for the oven. I meant for the IT to be longer (long story) with "ideal in the middle," but it should still work because...


...the base hinge adds ~2cm when the arm is flat from the smaller hole, which is intended as the pivot point. The disadvantage of the version we made is the arm length will vary slightly depending on the angle of the IT arm. I figure I can work around this by adjusting the arm to compensate as the angle increases. In our defense, we were on a very short timeline and improvising with what we had available. I think this should work fine.

My apologies for the dark pics.

[UtahBeehiver]

The reveal for the door being 1 cm is a little small 1" or 2.54 cm is recommended. Since you want to go with soldier, you can cut the top of the soldier to better match the interface of the dome half header dome bricks.

[TxGR]

Here are some drawings, sans dimensions, but setup for bricks 23x 11x 7cm. Soldiers for first course, then half-height.


Front view, brown is opening, red is soldier course, blue is flue.


Rear view. Arc starts 11.5cm above floor (lower green line).


Side view, first two columns in red represent two brick arches/opening, bricks laid as headers, stacked three, then arching.


Top view, blue bricks are soldiers, black bricks are first course of opening/archway. The lower bricks are intentionally offset toward the outside by 1cm for the door to rest against. The light blue is where the flue will go.

For the flue, I bought an 8" anchor plate, 8" double insulated 24" long pipe, and a very cheap 8" rain cap.

[TxGR]

Thank you for the feedback. I spent quite a while looking for the post. Perhaps I just don't understand the logic behind the search function in this forum software, but searching "buttress," "lateral forces," and "vertical forces" failed to generate any posts by Tscarborough. I even tried to search all of Tscarborough's posts, but the options ("date late updated" or "replies" failed to return any results newer than 2017 (and despite selecting descending and then ascending, the dates were not in order). I did try to find it. In any case, my dad (a mechanical engineer) thinks I will be fine. He is laying out each brick on his CAD application now.

I found some other posts, mostly having to do with buttressing the chimney area.

Thanks for the heads up of the center of the L bracket.

[UtahBeehiver]

You can use full soldiers, many have done for various reasons. You just have to be aware of the "potential" of needing to buttress the soldiers due to the outward force of the dome at the soldier and dome intersection. There was a recent post (last 2 weeks) showing the lateral and vertical forces of various arch configurations (it has been posted by Tscar originally.. Just something to consider. I used JCG31 IT design, so pay close attention to the center of the L bracket should be at 3.5 cm (7 cm divided by 2).

[TxGR]

While I am still in Texas, I am working with my dad on building the "indispensable tool" and working out some design/build questions. Since the bricks, hearth, etc. are all metric (23 x 11 x 7 cm), I am sticking with metric dimensions.

My current plans call for:
- internal radius of 55cm.
- first course of bricks will be full-height soldier bricks
- 180* arc of the dome will start about half-way up the bricks, at 11.5cm above the floor
- opening will be 52cm wide by 40cm tall (again, the arch will be a 180* arc, but the arc will start being measured from 11.5cm above the floor
- with 40cm tall opening on dome with 65.2cm internal height, the opening is 61.4% of dome height, close to 60-65% (63%) optimal size

The reason for raising the base straight up 11.5 cm for measuring arcs is to provide some more vertical access.

Currently, I am searching for various ideas on options for finishing flue and entrance.

I'll post pictures and information on IT once we finish it. We're going with an adaptation of the design posted by JCG31:
https://community.fornobravo.com/for...b-theme?t=2985

[TxGR]

While I've been away, they did pour the walls and top of the hearth. Here are the pics. Based on the pics, I think I did well and at a fraction of the price in the US.









The hearth after the pour looks a little rough, but very sturdy.


The rendering here is still drying, but I think it will look kind of like stucco when done.


I am looking forward to returning so I can start laying tile and building the oven.

[TxGR]

These are pictures from my last day covering the pour.

Just before the pour:


The cement truck was in the driveway, and they poured cement into wheelbarrows:


Then they dumped it in the form:


...and smoothed it out:


At first, I was quite worried about the irregular surface.


However, as the slab cured, they kept returning and smoothing it out. In the end, I was very pleased with the rough/non-skid, but even/level surface:

[david s]

I was considering tiling the hearth around the oven, but I suppose I could tile the hearth first, then build the oven on top. Given the weight on a dry surface, I can’t logically come up with a reason against it, but something about building on top of a hard, slick surface of a tile just seems like an error. That reminds me, I need to tell the contractor to prepare the hearth surface for tile.

thanks

Where the base of the dome meets the supporting slab is often an area that develops a crack which can then provide a path for water entry. A cement shell meeting a glossy tile is likely to result in a less than ideal bond. It is also a good idea to slope the supporting slab away from the dome to discourage water pooling at the dome base and possibly running under the dome. This can be achieved with some leveller before glueing any tiles down.

[UtahBeehiver]

Use a coarse surface tile or something else, pavers, etc. The main purpose is to get the CaSi off the hearth surface.

[TxGR]

I was considering tiling the hearth around the oven, but I suppose I could tile the hearth first, then build the oven on top. Given the weight on a dry surface, I can’t logically come up with a reason against it, but something about building on top of a hard, slick surface of a tile just seems like an error. That reminds me, I need to tell the contractor to prepare the hearth surface for tile.

thanks

[UtahBeehiver]

IMHO, you are better off using local ceramic tiles to raise the CaSi off the hearth. I can send you a cut sheet for FoamGlas if you PM an email address. Distribution International out of Houston use to carry FoamGlas, I got mine from them at a local branch office here in Utah. Not sure it is worth the effort be haul back to Thailand.