Why do you cut the bricks?

[wg_bent]

Looks like the bricks in the Pompeii oven are cut in half...Why? Can't you use whole bricks laying on their side or end? Sure it won't be quite as perfectly round, but the only way you'd notice that is if you stuck your head in the oven.

[Dutchoven]

Wg if you lay the full length(9 inch) brick to make the round structure of the oven the mortar joints become thicker and therefore are a bit more likely to fail. If you lay the brick at its full length with the end facing inside the thermal mass of the oven is larger and will take longer to heat up but, will give you heat for longer after the firing. Many french bread ovens were built in that way. Cutting becomes a necessity as the rings get smaller at the top of the dome as well and it is a slight bit easier to cut the trapezoid from the shorter brick.
Hope this helps!
Dutch

[dmun]

The short answer is that bricks are MUCH more stable than mortar, no matter what mortar you are using. There is a persistant problem with cracking in homemade ovens, and the reason is that there may be too much mortar even with the half brick design.

Some of us have gone to great length to reduce the gaps between bricks for just this reason. This involves brick cutting. The good news is that with a modern 10 inch diamond wet saw, the standard low-duty fire bricks are easy to cut, even easier than common red brick.

Of course you can lay up whole bricks in reducing polygons, but without an edge facing in, you reduce the reflection of heat back to the oven floor which is the way that pizza is cooked.

No matter how you decide to proceed, keep us posted. We love pictures and stories of oven construction.