Need to Isolate Dome Wall from Floor?

[bseiter]

I thought I read in another post (in passing) that the dome wall should be isolated/not mortared to the floor. However, I just searched for more info about this in the forum and cannot find any such advice. Does anyone know if this is needed/required? Does it matter if the dome wall is built on top of, or outside of the floor?

Any help would be greatly appreciated. Waiting for hearth slab to cure, then on to vermiculite layer, and then dome...

Bret

[nissanneill]

Hi bseiter,
there are two trains of thought with your query and you need to decide which way to go.
I built my dome with the full height soldier course (the first row standing vertically) directly onto the vermiculite insulation base and then cut the floor hearth bricks to fit. This allows you in the extreme case to replace any floor bricks if they wear or are damaged much more easily). It also keeps the outer perimeter clean and more easily clad with insulation than having to cut the corners off the hearth bricks that would protrude beyond the dome courses.
It really doesn't make much difference unless you plan on using your oven commercially and wearing out say the entrance bricks.
Russell Jeavons (the author of a good wood oven build and cooking book) uses 2 layers of 2" fired clay pavers for his commercial oven hearths with the view of lifting the top layer and replacing it if/when needed.

Cheers.

Neill

[bseiter]

Thanks, Neill, for your reply. More specifically, my question is:
1) If I lay the first course of dome bricks on TOP of the floor, do I need to take care to NOT mortar them to the floor? Does the dome need to "float" on top of the floor bricks - to allow for for potentially different rates of expansion and contraction from the floor?
2) If I cut the floor bricks to fit INSIDE the dome wall, do I need to leave a small gap between the dome and floor bricks - for the same purpose?

I thought I read in a post somewhere that this was recommended, but now cannot find reference to anything like this in the forum...

Bret

[Ken524]

1) Yes. If the first course is on top of the floor, don't mortar the bricks down. The dome should be simply sitting on top of the floor.

2) If the floor is custom cut to fit inside the dome (I used this method) leave a small gap. I used one layer of corrugated cardboard (cut from an old shipping box) to maintain the gap. The cardboard can be removed or left in after construction. It will burn out and the gap will eventually be filled with ash. You'll never notice it after your first fires.

Good luck with your build!!

[texassourdough]

Good, practical advice, Ken! And well stated!
Jay

[lwood]

Where is "the gap"? (not the clothing store)

[Ken524]

Originally Posted by lwood

Where is "the gap"? (not the clothing store)

Take a look at this post:
http://www.fornobravo.com/forum/21/m...html#post15367 (My Old Kentucky Dome)

The text and photos show it pretty well (I think!).