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-   -   Barrel vault with flat roof (http://www.fornobravo.com/forum/f43/barrel-vault-flat-roof-20027.html)

edd91 10-11-2013 05:29 PM

Barrel vault with flat roof
 
Hi all,

I'm considering in the future replicating one of the large NY styled coal fired bread ovens, which are essentially large barrel vault ovens.

It seems to me however, that the lower the angle of the roof the better. Of course with a vault, there needs to be a sufficient angle to hold the roof up with keystones. I remember reading a website with an old textbook how the flatter the roof the better.

My thought is could a flat roof be done through a keystone method, using the same type of method you see in the Colosseum in Rome, picture here, http://3.bp.blogspot.com/-sQ3AnxLvgQ8/TbxxC0J3dYI/AAAAAAAACJs/KoU_9xRIcxw/s1600/IMG_2875.JPG

Perhaps between each row of bricks you could have an upsidedown T shaped strip of steel supporting the edge of each brick.

Any thoughts?

david s 10-11-2013 06:02 PM

Re: Barrel vault with flat roof
 
The flatter the arch is, the greater is the sideways thrust. I built a kiln once with a flat roof using threaded steel rods through the centre of the bricks. About six in a row from memory.With the bricks bolted together in this way they can simply sit on top of the walls in the same way as a solid lintel. It works ok and eliminates the sideways thrust problem.

mrchipster 10-11-2013 07:49 PM

Re: Barrel vault with flat roof
 
Quote:

Originally Posted by edd91 (Post 163387)
Hi all,

I'm considering in the future replicating one of the large NY styled coal fired bread ovens, which are essentially large barrel vault ovens.

It seems to me however, that the lower the angle of the roof the better. Of course with a vault, there needs to be a sufficient angle to hold the roof up with keystones. I remember reading a website with an old textbook how the flatter the roof the better.

My thought is could a flat roof be done through a keystone method, using the same type of method you see in the Colosseum in Rome, picture here, http://3.bp.blogspot.com/-sQ3AnxLvgQ8/TbxxC0J3dYI/AAAAAAAACJs/KoU_9xRIcxw/s1600/IMG_2875.JPG

Perhaps between each row of bricks you could have an upsidedown T shaped strip of steel supporting the edge of each brick.

Any thoughts?

Heat containment with steel inside the firebox would create a high heat loss possibility, steel would need to be stainless, carbon steel would not hold up if exposed to direct flame.

I think a true flat ceiling would not provide the ideal heating you expect because the corners would not heat evenly due to lack of circulation of hot gasses in the corners and the excessive mass that would be required in the sides of the oven to support the outward thrust of an almost flat ceiling.

brickie in oz 10-11-2013 09:40 PM

Re: Barrel vault with flat roof
 
Quote:

Originally Posted by edd91 (Post 163387)

My thought is could a flat roof be done through a keystone method, using the same type of method you see in the Colosseum in Rome, picture here,

The arch in the picture is indeed flat(ish), but the blocks have slipped over time, even they were not subjected to an oven heat/cool cycles and yet they still moved.
There would be massive buttressing to hold up the weight of the blocks.

TropicalCoasting 10-11-2013 11:33 PM

Re: Barrel vault with flat roof
 
dont fear the dome

stormy 10-12-2013 06:17 AM

Re: Barrel vault with flat roof
 
Flat roofs are held up by springs, all thread rod and angle iron. The sides are laid up, a temporary support is installed to hold up the roof while it is laid out, angle iron down each side of the wall with a hole at each end for the all thread rod to go through. The springs are put over the ends of the protruding all thread, a washer, a nut and it is all tightened down. The springs hold it all in place as the roof heats and cools . The all thread rod is outside the firebox so it does not get exposed to the extreme heat inside the chamber.


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