How thick a mortar gap with "horizontal" soldiers? Tools, Tips and Techniques Discuss How thick a mortar gap with "horizontal" soldiers? in the Pizza Oven Design and Installation forums; I have opted for a horizontal soldier course instead of a vertical course to eliminate the large mortar gaps that ...

[kebwi]

I have opted for a horizontal soldier course instead of a vertical course to eliminate the large mortar gaps that vertical soldier courses suffer from. So my "soldiers" (something of an abused term in the horizontal case, unless they're sleeping on duty) will consist of three layers of bricks stacked horizontally, the first layer at floor-level (around and at-level with the floor), the second and third layers form the first rise of the wall (thus my dome will have a five inch plus mortar gaps vertical rise before beginning to curve).

I understand that in the curved sections, one should ideally shoot for a minimum mortar gap, none if at all possible, which makes sense since the gap on the outside of the dome will provide plenty of space for mortar. However, in the case of flat stacked bricks, no mortar gap would truly amount to NO mortar gap; I could conceivably lay the bricks face to face with no mortar or just a film of mortar that squeezes out tight.

Or, as with conventional horizontal bricks in most brick work the world over, I could actually lift the second and third soldier layers above the layer beneath them by a purposeful gap and fill the gap with mortar.

So, what's the best approach here? Thin film, squeezed out tight, with no true gap at all or an intentional lifted gap? If the latter, what should I shoot for? 1/16", 1/8", something else?

[jmhepworth]

I believe it depends on what you like. I've seen many ovens with a visible mortar joint on the inside, and others with as little as possible. They all seem to work. I like the look of the bricks touching each other on the inside, and since you can't see the outside after the enclosure is on, I wasn't bothered by mortar gaps on the outside (but I could have done without the expense of all that mortar).

[Tscarborough]

It is not a soldier unless it is on end and the narrow side is "exposed". You are laying "stretchers" so long as the narrow side is exposed and horizontal. Regardless, the idea is ALWAYS to have minimal joint at the face.

[kebwi]

Thanks for the clarification. I'm not quite following the "narrow side" / "horizontal" explanation, but otherwise, thanks for "stretcher".

My vertical bricks (stretchers) aren't full bricks. They are right-angle trapezoidal half-bricks, ala Lars' design (find his threads for a full explanation). I will post photos as I go of course.

[Tscarborough]

Here is a graphical explanation of brick positions and their names:

Hanson Brick - North America : brick positions

[dmun]

I understand that in the curved sections, one should ideally shoot for a minimum mortar gap, none if at all possible, which makes sense since the gap on the outside of the dome will provide plenty of space for mortar. However, in the case of flat stacked bricks, no mortar gap would truly amount to NO mortar gap; I could conceivably lay the bricks face to face with no mortar or just a film of mortar that squeezes out tight.

If I understand what you're saying here, you are starting your horizontal brick courses right on the floor, and avoiding the "soldier" course entirely. The answer is pretty simple: You lay your first course right on the floor, no mortar needed except a little to fill in between bricks. Your second course will start to tip inward to conform to the curve of the dome, and you'll have plenty of room for mortar in the outward tilted section. There's no particular reason to build the brick courses straight up: you're going to have to start tilting in sooner or later, and it might as well be sooner.

[kebwi]

Right, the first course, level with the floor bricks (but surrounding them) obviously won't be mortared to the InsBlock. I know that. I was inquiring about mortaring between that course and the one above it...and the one above that...three nontilted courses producing an interior vertical side wall of 5 inches (plus any mortar gaps). I had been under the impression that a short vertical section around the base was recommended so as to get better use out of the shape of the oven...to be able to place items closer to the wall without having the ceiling get in the way. I thought that the whole point of a soldier course. What other motive is there for using a very different style at the bottom than for the rest of the dome?