Correct way to lay the first course?

[joemyself]

Hi All,

I'm building a 36" ID pizza oven. Are there any advantages/disadvantages to cutting the floor brick to a 36" diameter and then laying the first course outside of that, versus cutting the floor brick to 40.5" diameter and laying the first course on top of that? Please see photos for reference. It seems as if the latter would have more of a seamless transition.

[Dooozie]

I'm in the middle of my build and learning as I go so I'm definitely no expert. I started with my floor bricks cut to the outside diameter so the dome would be built on top. I had real trouble with the smallest cut bricks moving on the very thin layer of sand which was there to help level them on top of the insulation (the floor bricks aren't fixed with mortar) I ended up re-cutting the floor bricks to the internal diameter with the first dome course of half bricks surrounding them.

This made a much better stable start to my build and I wish I'd done it to start with. I'm sure it's been done the other way by lots if people with success but I struggled with it.

[jjnevis]

Like Dooozie, I'm learning as I go and in the middle of my first build so no expert either. I asked the same question and the consensus seemed to be that you can do it either way. The advantage of building your wall on the floor (which I did) is that you don't have to be too accurate with your floor brick cutting and you don't need to worry about the expansion gap between the floor and the wall bricks. The disadvantage is that it's much more difficult to replace floor bricks, if necessary. Using this method, the bottom of the wall bricks are not bonded to the floor bricks to allow for small movements during thermal cycling.

[joemyself]

Many thanks to both of you for your insight!

[RandyJ]

You can do it either way. When i built my oven i cut the floor to the size i wanted then used a strip of cardboard to maintain the gap evenly. I didn't want things moving to much and causing cracks. As far as i know i had no cracks in the oven when i sold that house. I had offered to come teach the new owners how to use the oven and that i could bring a friend that was a professional chef who loved cooking with the oven. Never heard back from them so i hope they figured it out

[MarkJerling]

The one advantage of having the floor inside the walls is that the floor can be replaced more easily in future, should it be necessary to replace the floor. The magical question, of course, is: How often would it be necessary to replace the floor? I think, under normal usage, probably never. LOL So, no easy answer. I did build my floor set inside my dome though. My reasoning was that I used 40mm thick floor bricks on sand and I did not know if that would be thick enough. So, should I ever want to fit a thicker floor, I can. As it is, I think the 40mm thick floor is fine.

[joemyself]

You can do it either way. When i built my oven i cut the floor to the size i wanted then used a strip of cardboard to maintain the gap evenly. I didn't want things moving to much and causing cracks. As far as i know i had no cracks in the oven when i sold that house. I had offered to come teach the new owners how to use the oven and that i could bring a friend that was a professional chef who loved cooking with the oven. Never heard back from them so i hope they figured it out

That's so kind of you to offer that, I would have jumped on that offer immediately! Shame that they didn't take you up on it. Anyways, thanks for the info!

[joemyself]

The one advantage of having the floor inside the walls is that the floor can be replaced more easily in future, should it be necessary to replace the floor. The magical question, of course, is: How often would it be necessary to replace the floor? I think, under normal usage, probably never. LOL So, no easy answer. I did build my floor set inside my dome though. My reasoning was that I used 40mm thick floor bricks on sand and I did not know if that would be thick enough. So, should I ever want to fit a thicker floor, I can. As it is, I think the 40mm thick floor is fine.

You make great points!! Thanks for the info!

[fox]

I always build the dome on top of the base as this allows for expansion and cotractison of the floor mass.
On a less important note, it also allows a much quicker build as you don't have to precisely cut every brick to fit.