My Modified Barrel Vault in Texas

[perks1018]

Re: My Modified Barrel Vault in Texas

Your welcome. Angus was my constant if not particularly helpful assistant throughout the months of construction. I calculated the bevel on the bricks to allow for a specific number, in this case fourteen, bricks laid edge to edge to create a 9" wide by 2.5" thick vault. In this case, I wanted a semicircular vault with an 18" height so using all of my highschool geometry figured that meant a 36" inside diameter circle, roughly 39" outside diameter. 36" times Pi equaled a number divided by 28 yielded yet another number which when divided into the 360 degrees of the circle yielded yet another number which when divided by 2 (the bevels on each side of the brick) gave me 7 or so degrees. That is what I shaved off the long side of each brick using a 14" diamond blade in a chop saw. I cut a couple of wooden wedges at 7 degrees, propped the brick on them, then trimmed the brick. A running bond does not a stronger arch make. Each brick in any arch is bonded on every side to another brick or two. What a running bond provides is a greater number of individual or different bricks- 6 instead of 4- for any given brick to be attached to. Look at any brick in a wall and count the number of bricks it has contact with and you'll see what I mean. A running bond simply makes the failure of any individual joint less catastrophic. Finally, as I said before, the flue in the vault was a mistake, but one Im glad I made. My damper consists of a 3/8" thick steel plate backed with a thick pad of fiberglas which pivots at one end on a 3/8" steel rod running through a steel tube running through the masonry and out the front of the oven. When I turn the handle, the plate pivots up and the flue is open. Back and the damper is closed. Without the damper, my oven would have been a fireplace. I can start my fire without accelerants while the damper is open, and when the large logs are burning merrily, I can close the damper and heat the oven. We were baking pizza two hours after I lit the oven last night.

[david s]

Re: My Modified Barrel Vault in Texas

In kiln construction the end walls on a barrel vault should be inside the arch. If outside the arch steel bracing is used to prevent the end walls from tending to fall out. A large diameter arc exerts considerable lateral force at its base, a semicircle much less so and a catenery arch the best, although only if its base is about the same as its height. We are not building kilns so the temp extremes are not as destructive but the principles are the same.

[brickie in oz]

Re: My Modified Barrel Vault in Texas

Also, wouldn't it have been even more structurally sound to offset/ alternate the bricks in each vault ( or is this unnecessary)?

You have to bond the bricks to achieve optimum strength, this makes the arch as one rather than a series of single arches, and less likely to fail
See here.

Finally, does having the flue in the vault itself--as opposed to a separate chamber--have any negative issues associated with it (e.g. starting problems, heating issues/cold spots etc.)?

My flue is inside my oven and operates way better than I had hoped it would, lighting the oven is an absolute breeze, as for loosing the heat at shut down you just need a damper in the flue.

Chimney.

Flue Damper.

[david s]

Re: My Modified Barrel Vault in Texas

If the flue is inside the oven chamber you need a damper, or like many kilns, simply a cap on top of the chimney. Without such an arrangement every time the door is opened all the heat from the oven goes up the fue.

[luca]

Re: My Modified Barrel Vault in Texas

First, let me thank you for posting your pics; they are great (I particularly like your dog trying out the cooking surface!!). Second, I'm planning to start my barrel vault in August (still collecting supplies and waiting for grown kids who want to participate), so I've got a couple of questions. This one is for the moderators: This thread has been all about arches/vaults and possible collapse, but it looks to me like Perks tapered his bricks. Isn't that what arches are all about anyway? Now my question for Perks; I'm not sure how you did the tapering of each brick, so could you give me a little lesson (especially whether I need any special jigs/equipment etc.). Also, wouldn't it have been even more structurally sound to offset/ alternate the bricks in each vault ( or is this unnecessary)? Finally, does having the flue in the vault itself--as opposed to a separate chamber--have any negative issues associated with it (e.g. starting problems, heating issues/cold spots etc.)?

[david s]

Re: My Modified Barrel Vault in Texas

I don't recall what was on the other side of the vertical walls supporting it, I was just really amazed that the arch remained after so long and everything around it has failed.

[brickie in oz]

Re: My Modified Barrel Vault in Texas

But isnt the old arch buttressed? Looks like it from here.

[david s]

Re: My Modified Barrel Vault in Texas

This is an arch from the virtually deserted fortified town Oppiede les Vieux, Provence, France. The arch is about 600 years old and everything around it has failed yet it stands strong because the stones are shaped to fit. I think your oven will outlast you and a few generations to boot.

[KraemerBAC]

Re: My Modified Barrel Vault in Texas

Looks great. I wish I had added counters to my project

Thanks for the update

Peter

[perks1018]

Re: My Modified Barrel Vault in Texas

Not at all. Not offended, just completely freaked out! Anyway, all's well and all that stuff. Thanks!

[brickie in oz]

Re: My Modified Barrel Vault in Texas

Glad now I didn't try.

We are too.

I hope you didnt get offended by any of my statements, its just that arches do fail without sideways thrust, its a fact, I dont make it up.

[perks1018]

Re: My Modified Barrel Vault in Texas

I would stop right where you are and reconsider.

I couldn't, I didn't, and I'm done. I know advice in this forum is well-intended, but no disrespect, I'm glad I ignored some of it.

[perks1018]

Re: My Modified Barrel Vault in Texas

Final dimensions for the interested: 17.5" by 8.5" oven mouth, internal 31" deep by 28" wide, 17" height at peak. 43" by 43.5" outer oven dimension. Overall counter length 12' by 26" wide.

[perks1018]

Re: My Modified Barrel Vault in Texas

Wow. I had forgotten about the photobucket thing. Anyway, I brought it up to date- it is showing them in backward order so you don't have to look at the whole project if you don't want to. The little curly item at the top of the outer arch in the final photos is the damper handle- a cast iron lizard. Nose up, damper closed; nose east, damper open. Facing material is tumbled marble- noce, chiaro, and gold. Pictures by perks1018 - Photobucket
By the way, thanks for all the support. I got weepy and suicidal (almost) when I started second guessing the vault (after it was too late to really do anything about it). Glad now I didn't try. ;{)}

[Les]

Re: My Modified Barrel Vault in Texas

Anyway, I'm trying to figure out how to post them .

Do you want to post them in your thread or the gallary? If it's in this thread, just select the paper clip thats to the right of the happy face. I recall you can only upload 4 or 5 at a time. If the file is too big.... you'll figure it out