Soldier or no soldier? Pompeii Oven Construction Discuss Soldier or no soldier? in the Pizza Oven Design and Installation forums; Does the soldier layer really serve a function? Is it structurally necessary? Why not just start right out laying identical ...

[goodgulf]

Does the soldier layer really serve a function? Is it structurally necessary? Why not just start right out laying identical courses?

[nissanneill]

goodgulf,
you can look at soldier courses in a couple of ways, The height of the soldiers will depend on how you intend building your oven.
If you check out my build, (see signature below these comments) I cut a 15˚ angle off the top which helped kick the next course without a lot of mortar gap. I used full brick height because I cut and laid my hearth bricks inside the soldiers. Some people cement/bond their first course on their hearth bricks and others cut their bricks in halves and cement them as soldiers with the narrow side of the brick making the inside dome wall. These bricks (soldiers will only be around 3" wide when the bricks laid on their large flat surface are 4 1/2' wide. It really depend on the individual.
Others are almost paranoid to ensure that the inside of their dome is perfectly semi spherical and cut the base course of bricks accordingly.
Yep, decissions, decissions and even more decissions to make throughout the build.
I am not quite sure that I understand what you mean by your comment "identical courses"! Every course (or as some people call them chains) in your oven build vary in diameter and angle. There are no two courses the same! and different number of bricks. Some even cut their bricks into thirds rather than halves for the higher courses. You also need to maintain a good bond when you lay your bricks and ensure that you don't have mortar joints aligning as you are building in a weakness into your dome.
You will experience this once you start laying your courses.

Neill

Neill

[dmun]

Does the soldier layer really serve a function?

No. It's traditional. I suppose you could argue that it gives you a little bit more shoulder room in the chamber if you're packing it wall to wall with loaves of bread, but most of us don't bake like that.

Is it structurally necessary?

In my opinion, it's structurally suspect. The hemispherical dome is very strong - setting up a bend in the curve significantly weakens it, I think. This is particularly true of the full height soldier courses. I'm not a structural engineer, nor do I play one on TV.

Why not just start right out laying identical courses?

Why not indeed? There is no reason for not putting your first course right on the oven floor.

[Dino_Pizza]

I used to think the fuller height soldier course helped with taller casseroles or beer can chicken (any vertical chicken holder) but these things tend to be in the center of my oven anyway and always have enough room.

If I were re-doing my oven, (just my musings for what its worth ) I think I might use a shorter soldier on my 42", however if I was building a 36" or less oven, I would think I would have stuck with a taller soldier to eek more room out of the perimeter. But like dmun says, it's not structural necessary.

Good luck, Dino

[kebwi]

I'm facing this too, although I'm really down to the wire on changing my plan. I'm pretty committed at this point. But my thoughts reflected yours Dino_Pizza. I'm building a 36" so I opted for a short vertical wall before curving inward to increase the usable area. I'm not using vertical bricks, so they aren't soldiers, but my dome design has a vertical rise before curving inward (from two flat courses stacked 5" high to the first angle

Another advantage of a vertical side wall is that it better approximates the Neapolitan profile of a flatter (than otherwise) ceiling, for better searing a pizza...but I think it has been well established on FB that such design considerations venture well beyond noticeable benefits.

[Tscarborough]

"In my opinion, it's structurally suspect. The hemispherical dome is very strong - setting up a bend in the curve significantly weakens it, I think. This is particularly true of the full height soldier courses. I'm not a structural engineer, nor do I play one on TV."

A true hemispherical dome places no outward thrust upon it's foundations. The flatter the dome gets, the more it does so, but so long as the dome is kept round, bonding mortar is used, and it is without interruptions, i.e. openings, the forces are minimal. For a typical oven that is parged on the outside, I don't think it matters a whit how you do it.

[Neil2]

"A true hemispherical dome places no outward thrust upon it's foundations."

Yes it does. All domes, hemispherical or elliptical produce outward thrust.

[Tscarborough]

I stand corrected, they do indeed produce outward thrust.

[goodgulf]

Ah, the point that I was missing is that the soldiers raise the walls above the oven floor. I prefer the idea of building right on the floor and skipping the soldiers.
This does raise a question: are the firebricks structurally sound enough to support all the mass over time? Is there a concern about them deteriorating at all?

[dmun]

This does raise a question: are the firebricks structurally sound enough to support all the mass over time? Is there a concern about them deteriorating at all?

They've been made almost the same way for over a century. People are now doing builds with reclaimed ones from heavy industrial service, and they're dirty, but sound. Also, unless you're building a two story masonry chimney like I did, they're supporting only themselves.