Brick Layout and Spacing

[CapePizza]

I'm on the verge of starting to order materials and start a 32 inch Pompei oven. I've been working out the design in CAD which will give an idea of how many bricks are needed. Also to get more educated about how the arch is designed, one area that's been really kind of perplexing. Even in CAD it's a little tough to figure out but I think I'm getting a picture of how it should come together. But right now my big question which maybe someone can offer some guidance with has to do with the spacing between the brick. I'm planning on cutting a taper on both sides of the brick to get more surface contact between each brick as each row makes its way around the circumference of the oven. Cutting the tops and bottoms of each brick (tapering the tops and bottoms) seems like a lot of cutting. But not tapering the tops and bottom seems to leave a lot of open air (space) with what will basically get filled with mortar. Is there a rule of thumb how much mortar becomes too much? From the images attached I can see there very last couple of rows it seems like there's going to be some tapering necessary on the bricks to reduce the amount of air and provide more surface contact from brick to brick. Any thoughts, suggestions and guidance would be appreciated and helpful. Thanks very much! Any generalized comments would also be welcome. Thanks!

[Kvanbael]

Yes indeed, there's many bevelling and tapering choices for the dome: Here's the full menu:

1. (higher rows only) Use bricks that are less wide to avoid rows with very few bricks.
2. (higher rows only) Make the top of the brick narrower than the bottom, to avoid the inverted V's gaps
3. Inside of brick less tall than outside of brick, to avoid large horizontal joints on the outside
4. Inside of brick narrower than outside of brick, to avoid large vertical joints on the outside


You don't have to do any of these. You could build an oven with the layout shown in your drawing. The mortar should be able to fill the gaps.

However, the vast majority on the forum seems to opt for at least 1. and 2, as it looks prettier from the inside and exposes less mortar to the direct flames.

Some people also opt for 3 and/or 4. I suppose this is for increases stability (in theory such a dome could be dry-stacked) and to use as much firebrick mass as possible. But note that those options involve a *lot* of cutting. You'll need more time and more bricks.

[CapePizza]

Thanks for the reply and suggestions, Kvanbael. I re-revised (again) my CAD and am feeling better about the joint spacing. As you suggested, the areas where the bricks meet on inside of dome are now tight and there is a bit of open space on the outside of dome bricks... so should be enough for the mortar to take grab. I was trying to avoid having to cut so many bricks but I think I've reckoned with the fact that to build this "right" I'll have to cut many of them to fit the way I'd like them to fit, and have more surface to surface contact where is needed. I had actually been looking at photos of your build...so thanks for sharing.

[mongota]

What Kvanbael mentioned, minimizing the amount of mortar exposed to the flames is what I did. I didn't shoot for mortarless joints. Some have. For joints that would see fire, I generally went for about 1/8"-3/16".

So I only tapered the sides of the brick, from front-to-back as well as from top-to-bottom. I left the 2-1/4" thickness alone.

You can make both tapers in a single cut, and it's easily repeatable if you have a wet saw and a jig for the saw table, the jig will allow you to repeat cut after cut. I left the 2-1/4" thickness alone.

I used half bricks for the lower course and transitioned to third-bricks for the upper courses. Your dome will tell you when to change.