dome built on top of or around oven floor?

[dougrappe]

Hi everyone, back at work on my 36" oven now that the weather is nice. I'm hoping someone can convince me one way or another how to place the oven floor. I have seen the two different methods of dome construction, one with the dome walls sitting on top of the fire brick floor, the other with the floor inset within the walls. It seems that some of the more recently built ovens are using the second option, is there a distinct advantage? I have a wet-saw so the extra cutting isn't really a problem, just wondering why some of you have chosen one method over the other.

As the hearth slab is curing, I'm interested in laying out and precutting as much as I can. THANKS!

Doug

[Ken524]

Re: dome built on top of or around oven floor?

Hi Doug,

There have been a few debates on this issue on the forum. I used option #2 for my oven (floor inset within the walls), but I'm convinced it makes no difference whatsoever.

The mass of brick used is exactly the same with either method. Any difference (if any exists) would be splitting hairs. Adequate insulation over, under and around the oven is far more important.

If you go with option #2, make sure you leave a small gap between the floor and walls to allow for thermal expansion of the floor. I put some cardboard around my floor bricks to leave the small space when I built the first course of the wall. The gap will fill with ash after your first few fires.

If you build the walls on top of the floor, I suggest not mortaring the first course of bricks to the floor. This will allow the walls and floor to expand and contract without damaging the walls.

Build it they way you think it will be easier.

[dmun]

Re: dome built on top of or around oven floor?

Yep, no difference in performance. I built my dome on top of the floor because of less fussy cutting, but both ways work fine.

[Frances]

Re: dome built on top of or around oven floor?

I built my dome round the floor because I couldn't be bothered to work out how big to make the floor if I put the bricks on it... silly reason, but it still doesn't matter

[Modthyrth]

Re: dome built on top of or around oven floor?

LOL, and I built my dome on top of the floor so I could just set out enough bricks for the floor, not worry about precise cuts, and start building the dome more quickly. Both methods seem to work beautifully.

If I'd been doing a dome enclosure, I would have cut the bricks for the floor and done the ring on the outside.

[dougrappe]

Re: dome built on top of or around oven floor?

Thanks everyone, I guess I'll flip a coin Nice to have options, I am planning an igloo type finish, so I was planning to cut the floor fairly round anyway. (Although I'm still keeping my options open there.) I am really enjoying this whole process, and have been admiring all of your work for some time, it's nice to pick and choose among all the best details and solutions you all have come up with! Hope to contribute some of my own soon enough.

Doug

[Les]

Re: dome built on top of or around oven floor?

Doug,

One thing that comes to mind, that wasn't mentioned - If you ever need to replace a hearth brick (and I don't see that happening) it would be much easier if the dome wasn't sitting on it. And if you are taking count, I went with option #2. Like Ken said - what ever is easiest for you.

Les...

[Wood fired oven workshops]

Re: dome built on top of or around oven floor?

Les is right. The logic for having the floor bricks or tiles inside the dome is to replace them if needed.
I expect that unless you are using the oven 24 x 7 x 360, as in a commercial operation, it is unlikely you would need to replce decent hearth bricks in a lifetime.
With walls 'on' the floor it save an awful lot of cutting.

[Dino_Pizza]

Re: dome built on top of or around oven floor?

Hi Doug, great job on the base. The stone is really beautiful. You're going to have a great looking oven. Can't wait to see it.

But if you go with the soldier course AROUND the floor, you can leave them whole and just cut the tops at a slight angle to get your dome curve started. It makes for a tall, 6 1/2" base before you start curving the dome. (which I think is desirable)

Then again, you could cut the soldiers to any height you want on top of the floor too. So like Ken said, it's up to you.

Cheers, Dino

[rbigante]

Re: dome built on top of or around oven floor?

Has anyone used some type of barrier between their first course of brick and the floor (first course on top of floor) to prevent bonding of the first course mortar to the floor. I was thinking of cutting wedges of waxpaper. I figure it's non-toxic (i would think?).

[egalecki]

Re: dome built on top of or around oven floor?

I built mine on top of the floor- and I used newspaper strips to keep from mortaring the bricks to the floor. I think it worked ok. If you make them a little bigger than you need, it helps to keep the mortar off the floor inside the dome. I also used a big piece of tyvek inside to keep the mortar off the floor while building.

[rbigante]

Re: dome built on top of or around oven floor?

thanks elizabeth!

gave me an idea. i'm going to use plain old 8.5x11 paper cut to size. that should do it.

[fxpose]

Re: dome built on top of or around oven floor?

If you build the dome on top of the oven floor how far out can you extend the floor from the dome? Can it cover the entire hearth?

[rbigante]

Re: dome built on top of or around oven floor?

I extended my floor no more than 2 inches or so from the outside of the dome. I wouldn't go too far because it may make insulating a bit harder. my dome insulation (FB blanket) butts into my floor insulation (FB Board). If you floor extends too far from the outside of the dome, you may not be able to insulate properly or may have to add additional insulation that may otherwise not be necessary.

[christo]

Re: dome built on top of or around oven floor?

I was in a hurry and let my bricks fly long vs. cutting them to rough shape.

The whole bricks that extended got closer than 3 inches to my enclosure walls and metal studs - so I had to cut them after the fact. Sure wish I had just whacked them in half with a chisel when we laid the floor.

It was a pain getting a grinder in there and cutting them in half.

Christo