angle irons on corner installation

[gjbingham]

Anybody have thoughts on using angle irons on a Pompeii oven corner installation? The irons are intended to give support to the last layer of cement blocks spanning the opening in the base by laying across a significant portion of the adjacent 3rd layer of blocks. With a corner installation as described in the downloadable oven plans, it seems to me that the irons would barely be hanging on by their "fingernails". This is not discussed in the plans.
Seems like flat irons placed more internally in that portion of the base would gain more support from the previous layer of bricks and make the span across the gap stronger.
Thanks for any advice you can provide.
GJBingham

[Chris]

For what it's worth, I just poured the hearth slab across the gap, and did away with the angle irons. It hasn't fallen in yet!

[gjbingham]

Thanks Chris,
I considered that and that is what the pictures seem to indicate in the oven plans I downloaded. I reread some of the other text which talks about a sagging hearth, which made me want to post the question.
GJB

[Hendo]

I've never been able to appreciate why you'd want to sacrifice headroom of the opening by placing angle irons and a course of blocks above the third course, when you could just pour the hearth slab on top of the fourth course of blocks, using whatever method to support the slab during the pour.

Can anyone shed some light on this - is it purely for aesthetics? Or if it's for structural reasons, perhaps I'm missing something.

Like Chris' hearth slab, mine hasn't fallen down either!

Paul.

[nissanneill]

Hi Hendo,
to me all you need to do is have your concrete sufficiently thick enough (and I would anticipate between 4 to 6 inches (100 to 150mm) with some F62 reinforcing mesh (and I would double it over the unsupported hearh front. To add that extra strength, I would also put in a couple od 12nn reinfircing deformed bars (one top and the other bottom) ata round an inch or so from the surfaces.
This will support huge amounts of weight but remembering that the oven doesn't have much weight over that particular area of tour base. The opening and vent area taking up most of the room.
I would however prop the unsupported area until the cement slab has cured for at least a week or so.

Neill

[Hendo]

Neill - your thoughts accord with mine.

Perhaps someone involved in the development of the FB plans could shed some light on this?

Sorry to hijack your thread GJB, but I guess it's relevant to your inquiry.

Paul.

[Hendo]

Just noticed another example (at http://www.fornobravo.com/forum/f2/s...tand-2714.html (solid pour foundation and stand)) of a slab poured straight on top of the walls without a support lintel:



I don't think Drake's had any problems with his hearth slab sagging either!

And if aesthetics are an issue, you can always modify the opening with your veneer material, as Drake did. But at least you get the option of maintaining the headspace if you want.

Cheers, Paul.

[gjbingham]

Thanks all,
Good comments. I guess I'll give it a shot without the irons.
GJB

[DrakeRemoray]

No problems with sagging...

My construction friends assured me they pour thinner slabs over longer spans all the time...

Drake

[james]

I know the answer as to why we recommend the angle iron and course of blocks. Security. When we first wrote the plans and built the first ovens, we took the safe route, which has a lot going for it.

I am trying the U-shaped stand and thicker slab approach in my new oven -- which you can follow here:

http://www.fornobravo.com/forum/7/ar...html#post17127 (Artigiano 120)

Like of lot of things related to brick ovens -- dome height, opening size, vent design, dough hydration, etc., there is wiggle room in how you do it, and there really is no one "right" away. Rather, there are multiple right ways. Well, except for dough. :-)

James