First row of the dome

[1821]

Hello everyone, I need some advice. We've built the base and the floor of the oven and we are about to start the dome. I'm working with a union mason and he suggested standing the fire brick up on their ends for the first row of the dome. I've attached a couple of photos to show you what I mean.

Has anyone tried this? Does it affect the oven in a negative way. From here, he plans to split the bricks in half and build up the dome.

I have a few concerns, will this be too high of a dome? Is it needed?

Also, one last question, do we use fire bricks for the entire dome? Or, can we use regular bricks near the top. Many thanks, in advance, for your feedback.

[Les]

Re: First row of the dome

It's been done. I believe you will need to adjust the curve to maintain a proper height. Hopefully someone that went that route will chime in and give you better advice. The only reason to do this is to give you more room around the perimeter of the oven. I built a 42 and have no issues without the additional vertical space.

[deejayoh]

Re: First row of the dome

Search for "soldier course". Plenty of people build ovens this way. More common than using sailors (bricks laid on flat side). And use firebrick for the ENTIRE oven. Especially at the top. It is way hotter at the top of the oven than at the floor...

What is your under oven insulation? I ask because it seems like there are posts from lots of people who have a mason build their oven and have trouble getting them to understand the need for insulation under the oven. Can't tell from your pictures but it looks like maybe you have 2" of vermiculite?

You should download and read the Pompeii instructions, if you haven't yet. All of this is covered in there in great detail

[texman]

Re: First row of the dome

Use firebricks only in the whole dome and vent. Regular bricks will not work. Be sure and use the proper dome height/door size ratios of the performance of the oven will be diminished from optimum. Most builders here go with sailors there because of stability, but it can be done that way with soldiers. You can achieve the same "room" with rows of vertical sailors before you begin the dome transition. You should take a look at Les' build and you will probably change your mind.
Texman

[Tscarborough]

Re: First row of the dome

The issue is not height, it is lateral support. In ovens built like this, you will need external support. The Italians use a pumice mix backed up with wire (not lath) to provide the support. Here is how I did it by making a tensioned band of refractory concrete so that I do not have to rely on the external structure (I am using loose fill so it would have no lateral strength).


It is 42" with a 15" dome height.

[1821]

Re: First row of the dome

Thank you everyone, very much. I will do some additional searching for solider course. I really appreciate all your help. Many thanks!

[nissanneill]

Re: First row of the dome

To avoid reinforcing your soldier course, it is recommended to lay them on your base insulation rather than on top of your hearth. This will reduce their effective height bu the thickness of your hearth which id using bricks on their flat would be 3" or 75mm.
There are pics of my build if you want to see my build.
Cheers.

Neill

[dottavio]

Re: First row of the dome

As Les mentioned, it will impact the curvature of your dome. I went for a flatter dome and used the soldier course to give my dome more of an elliptical shape.

You can build either an elliptical or a spherical dome profile. Please keep in mind that with the ellipse the radius changes with each row.

[Dino_Pizza]

Re: First row of the dome

It looks like you've already got your oven floor "locked in" (with mortar around it) so I assume you cannot put the soldier course "around" the floor but will put it "ON" the floor. That's fine, it's how most of us do it now although mine went around the floor, and I built mine 3 yrs ago. Since you are putting your soldier or 1st course "ON" the floor, and if you leave it that full height, unless you are really careful, it's easy to let the dome height creep up too high. You have to be very vigilant at angling each row to keep the dome at 19" to 21" in the middle.

If you choose to use a true soldier course as you pictured it, (bricks on end/standing tall) I would cut an inch or 7/8" angle from the inside to the outside edge to get your dome curve-angle going. But you could also do as others suggested and not use a true soldier, but use a brick cut in half (like you will use on all the subsequent rows) and stack 2 rows before you start angling in or use a slight angle on your 2nd row/ring.

Also, remember there is no need to mortar that 1st course down, onto your oven floor. Just mortar the sides of the soldiers, let whatever drips down to the floor stay, (that you can't get clean up) and what little attachment there is, will break anyway at your 2nd or 3rd firing when the oven is done as it expands. Just don't mortar it to the floor or else you may get unexpected cracking. The weight of the whole dome will keep it in place and or any buttressing at the arches later on.

Good luck,

[shuboyje]

Re: First row of the dome

1821,

What are you looking for in an oven?

A soldier course like you picture is perfect for a low dome Neapolitan style oven. Is that what you are after? If you built a hemispherical dome on top of a soldier course like that you would end up with an oven that is WAY to tall, so if you are after a hemispherical oven this is not the route to go.

[GianniFocaccia]

Re: First row of the dome

Assuming you are paying your mason, why not ask him to read through a few FB posts to educate himself on design considerations and construction elements, including insulation? If a picture is worth a 1,000 words, about 15 minutes in the photos section should do it.