Advice required on preventing 3rd main chamber collapse

[Digga Don]

2nd build of arch, new form work, no plastic

[Karangi Dude]

Hi Digga Don, and Hi to you Russell
Don, as Russell said I only check in now and then but sending me a PM might get my attention as well
Don, it would be nice to see your photos so I can get a better understanding of your situation.
A low vault arch needs side buttress to support the downward thrust that is put on the walls by the weight of the arch, an arch will support itself but the sideways thrust has to be taken into consideration.
The outer steel that I used was to do just that become buttress, as this oven is on a steel stand that is almost 2 metres high I didn't want to build a brick outer shell for buttress, as you can see I used 50mm of fibre board then filled the void with vermicrete at 7 to 1.
Also building the side walls and the arch in bond certainly helps with strength.
Don I hope this helps you understand better and I look forward to seeing your photos also some sizing might help and a photo of the stand and the under hearth insulation
Cheers Doug

[UtahBeehiver]

Pictures can be attached using the "camera" icon in the upper left corner of the posting section. Pics are limited to 1.25 mg and about 5 per post. Karangi Dude, long time member, only visits periodically so it may be a while for a response.

[Digga Don]

I'm concerned about expansion of the steel and noticed your oven is the other way around. Im thinking i should change it?

i have pictures and a detailed drawing but i cant seem to attch them to post Any advice on that also

[Digga Don]

Karangi Dude
I have a couple of question around the metal support and insulation on your barrel vault.
I'm back on the horse after two traumatic collapses of my main chamber barrel vault. Both due to my error's , the first being plastic over the formwork which prevented the premix thin bed mortar Im using from drying on the inside in the Great lakes climate and insufficient buttressing. I removed the formwork, and it collapsed 3 hours later. The second arch which had a keystone flicked out from the skewback whilst I had temporary buttressing removed and excited with progress removed the formwork again. Whilst all the top courses where dry moisture and possibly frost had entered the mortar layer of skewback.

1 I was wondering if I should put a parge? coat over the main chamber with fiberglass render mesh or chicken wire in it to strengthen the whole thing?

2 I have installed steel supports on either side of the main chamber against the bricks with 0mm calcium board on the olutside.