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lwood 04-24-2010 03:58 PM

Brick Arch entryway problem
The arched entryway to my oven is being pushed off the oven dome by the expanding metal of the flue. I only used half bricks to form the archway and no reinforcement around the flue. I am ready to tear off the archway and re-do it but not sure how to fix it. Should I leave a space btw the archway and the flue to accommodate the expansion, also thinking about adding perlcrete to the outside of the archway. Any thoughts? Will get pics.:confused:

Les 04-24-2010 04:55 PM

Re: Brick Arch entryway problem
I need a picture. It's hard to believe that the flue is the cause. The flue should not be attached to the dome - it's sitting on top of the entry. Anyway, pictures help us all to understand what is going on, I'm sure we can solve this.


david s 04-24-2010 10:38 PM

Re: Brick Arch entryway problem
I had this problem when I built my second oven. I used a stainless steel flue pipe that was about 0.9mm thick. It gets hot first and expands. It cracked the castable refractory surrounding it. I now use thinner material which is 0.55 mm thick and I surround it with the slightly flexible vermicrete. No more problems at the join of the flue to the inner oven or to the outside shell. Take a look at the drawings page on my website.

lwood 04-25-2010 05:16 AM

Re: Brick Arch entryway problem
3 Attachment(s)
Here are a couple of pics

lwood 04-25-2010 05:27 AM

Re: Brick Arch entryway problem
I'm certain it's flue expansion, because when the oven is really hot, that gap widens to maybe 1/4" and I can't push it in to close the gap.

dmun 04-25-2010 07:12 AM

Re: Brick Arch entryway problem
If you rebuild that, i would expand the space where the metal flue interacts with the masonry and stuff it with some refractory blanket, for expansion. A quarter of an inch expansion seems like a lot to me, but I don't have time to do the calculation now.

lwood 04-25-2010 03:04 PM

Re: Brick Arch entryway problem
I didn't measure, 1/4" may be an exaggeration, but that's the flue bowing out, not the metal expanding 1/4". That's exactly my thought, leave more space and stuff it with flexible insulation. Thanks, I guess that's a heads up for everyone to use .55 mm stainless for their flue matl.

Tscarborough 04-25-2010 03:18 PM

Re: Brick Arch entryway problem
For the correct construction detail, Google "chimney cap construction detail".

That is certainly your problem, and it is pretty easy to fix without tearing apart the oven.

david s 04-25-2010 03:31 PM

Re: Brick Arch entryway problem
This is my solution. Seems to work pretty well.

lwood 04-25-2010 03:37 PM

Re: Brick Arch entryway problem
david you would put perlcrete extending onto the OD of the arch also? Is that correct?

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