Layout of firebrick on the dome

It says to start with a 1/2 brick and a full on the dome and end with a 1/2 and full. I am coming up a little short of a full and 1/2 at the back of the dome. Is it ok

I did the grande. It’s nineteen total rows of brick. Each row of the arch should be four full size brick and one half size brick. With mortar joints that should run the full length of the mold. When I built it out, I spent about fifteen minutes sketching it on my notes to make sure I had the right starting place for the half fire brick. Because there are an odd number of rows, each side should mirror the other until you get to the very top row, which has a full fire brick in the back and a half fire brick on either side of the chimney (for a total of two for that row).

I think the barile mattone is fewer rows and each row consists of 3.5 fire bricks. I hope that helps.

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Welcome to the BrickWood forums!

The row counts are based on a “standard” size firebrick that is 9 inches long. Unfortunately brick sizes vary and you often have to take what you can get. My supplier had 8 ⅜ inch long bricks. So I had to adjust most of my courses to account for the shorter bricks. Since I wanted to do that without shortening the length of the oven itself, that meant cutting a brick to a longer size at the end of each course rather than using a half-brick.

The most obvious outcome is that my courses did not lay neatly a half brick staggered. As long as you do not put one vertical joint directly over the one below it (to be safe and strong, a minimum of about 2 inches staggered should be enough) you will be fine.

You will also have to think through the very top row, which stands straight up and “caps” the arch. For that row, you’ll find that you need to set up a stagger pattern that does not coincide with the rows on either side of it. You can use a relatively short piece of cutoff firebrick to “push” the pattern away from the vertical joints on the adjoining courses.

Hope this helps!

Great thank you for your help.

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What size vertical joint should I be using go up the dome.

Keep them narrow. No more than ⅜ inch.

Your horizontals will be very thick but wedge shaped once you start getting up on the curve of the arch. They “enforce” the curve and also seal out hot gases from getting up and into your insulation.

Use the ridges in the foam to guide your horizontal mortar thickness. The top of each brick should always be flush with the ridge, and the inside face of each brick should be in full contact with the foam. When your mortar is laid in to achieve that, the brick will “automatically” be at the correct angle to form the arch.

So 1/8 to 1/4 would be acceptable? Thanks again your help

Yes, not only acceptable but ideal. You’ll get freaked out a bit because of how much mortar has to be laid in to the horizontals as you go up the arch, but it’s the interior that counts. Where they are flat (the first three courses) you want the narrow, even joints.

Good luck!