Reinforcing arch sides?

[gjbingham]

Re: Reinforcing arch sides?

I'm kind of kicking a dead horse 'cause Ken's already solved his problem, and it looks like a great solution. Sorry to run over your thread Ken. Perhaps more comments might further enlighten other builders as to the need for extra support in their respective situations.

I'm copying Ken's entryway arch setup (though it won't look nearly as good when it's done). I was thinking the same thing about needing extra support, especially since I was planning on placing a cast vent on top of the arch, which will ultimately attach to a Duravent system chimney. My casted vent weighs a lot..... probably 30 - 35 LBS. Also, I need 7 - 8 feet of chimney to get above my adjacent swimming pool enclosure. That's quite a bit of weight, huh? Am I expecting too much out of the arch? (Pic attached - note the highly technical use of a stepstool to hold the arch form at the correct height).

I read up on stone arches online. From my limited understanding, all the forces of the weight of the arch are transferred laterally, and thus, the reason all the great ancient arched walls had a ton of butressing.

Based on this, I would thing the majority of the stresses would be in the upper couple bricks and mortar joints of the walls, and would be the likely area of failure due to overloading the arch. Wouldn't you then think that additional buttressing would be most useful in the upper levels of the entryway/vent walls, or at least more important than the lower walls??

Sadly, Ken's/France's solution will not work on a my corner installation oven, as there is no place to mount the brackets.

Thanks for any comments.
George

[Les]

Re: Reinforcing arch sides?

George,

How much room do you have - enough for another row of brick?

Les...

[Frances]

Re: Reinforcing arch sides?

This won't help any of you guys, but it might interest others who haven't got this far yet...

I was worried about the stresses caused by the chimney, never having built an arch and seeing as my flue tiles are extremely heavy. So I kept the walls of the entryway streight, rested the (wide) vent on top and the chimney on top of that. All the forces involved just push streight down. The weakest point is the cast vent... we'll see how that holds up.

It strikes me as being a safer (though less beautiful) solution for heavy chimneys.

[christo]

Re: Reinforcing arch sides?

I got paranoid after building my arch and getting the enclosure built.

I used bricks stacked on the narrow edge for my opening and was really worried about the brick arch pushing out the sides. A cast vent would have prevented this worry....

So after I finished up the metal framing and adding the concrete board, I mixed up some concrete on the dry side and filled up the gap between my enclosure and the sides of the vent. I basically have an 80 lb bag of concrete butress on each side of my vent walls. I sleep better now....

I like Ken's idea with the insulating board next to the brick on the wall - I wish I had thoght of that before I added the concrete - even with that heat sucker - I don't feel I lose much heat that far away from the oven dome.

Good luck!

Christo

[gjbingham]

Re: Reinforcing arch sides?

That's a great idea Christo! I can't imagine that you'll have problems with the walls surrounded by that much concrete.

Les, I've got about 4 inches on either side of the front 2/3rds of the entryway/vent walls. This photo doesn't show the walls in place yet, but you can see that there's 8 - 10 inches back near the oven dome, where the hearth widens out, much less so out front.

Frances' cast vent over vertical walls makes the most sense, but I really liked the look of having the arches out there, even though they won't be seen(unless I go with an Igloo type finish). Ken's transition to the chimney is probably the lightest, least stressful way to go.

Perhaps I should use my cast vent for an anchor, or put plantings in it

George