Beginner with a foundation problem.

[SpringJim]

Originally Posted by herrbeckley

Thanks again for all the help. More explanation of cantilever is welcome. Just how would I do that on a round base?



TB

Don't overcomplicate it. The size of your base is?? You extend the hearth slab out beyond that base by the size you need. Use temporary support for your pour and I assume the reinforcing will exetend appropriately into all the cantilevered portion(s).

I was thinking recently about a mushroom oven. Drill a center caisson into the soil, pour a single reinforced column and then do a round oven base with interconnected reinforcing. Just like major columns used in highrise buildings. As long as you don't fly an airplane into the column, I think it would stand the test of time. (and no, no magic mushrooms for that one) We have some large diameter augers at work and drilling equipment....I've drilled a lot of holes!

[Dutchoven]

Originally Posted by james

Tom,

Build a form to support the concrete that hangs over the stand, use a flexible material such as thin plywood to shape the circle, and make sure that your rebar reaches over the stand to support the cantilever.

James

One additonal way of reinforcing the edge is to bend a piece of rebar around the outer edge and tie it to those that go across the block walls into the middle of the slab, similar to a bond beam. reinforced concrete should have no trouble holding your oven even if it were to stick outside of the block walls. That type of construction really would only be unstable if they extended out more than half the width of the area that was supported which would be in the area of 24 inches or so in your case. I think you will be pleased with the way it will look in the end. You should do a search on a place called "Falling Water" it is a house that Frank Lloyd Wright designed and there were many cantilevered concrete slabs that made the owner nervous but they are still there and are still structurally sound.
All the best!
Dutch

[james]

Originally Posted by Dutchoven

One additonal way of reinforcing the edge is to bend a piece of rebar around the outer edge and tie it to those that go across the block walls into the middle of the slab, similar to a bond beam. reinforced concrete should have no trouble holding your oven even if it were to stick outside of the block walls.
Dutch

Excellent advice.
James

[dmun]

Want an easy way to make a round base? The huge round reinforced concrete drain tiles for culverts even have holes in them for branch line intersections. When they replace them for road widening projects, they often break the old ones up and truck them away at great expense. I bet a few phone calls could get you a chipped or used one for free.

[herrbeckley]

All of this is extremely helpful. I hope to check in after this weekend and offer an update as to my progress. Thanks to everyone.

One last thing. I was looking at the website of Monterey Masonry and I was deeply impressed with both the shape and material use in the construction of that dome. My only questions would be, (and I know that there is a big discussion about this topic) how hot do you think that oven can possibly get for cooking pizza seeing as how he uses red brick and lime mortar? Also, the double layer of red brick is intriguing. Would this not do a better job of retaining heat than the normal cladding and insulation?



TB

[dmun]

You mean this oven?



Those are red firebricks. And there is a ton of vermiculite concrete insulation in that oven.



There is more mass in that dome then I would build, but clearly that was a design choice.

[herrbeckley]

Didn't realize that. I wonder how easy it is to find red fire brick. I think they look great.

TB

[dmun]

They're nice to get, I got them, but don't kill yourself if they aren't available locally. They are only red when they are wet, like they are in those pics. When they are dry they are sort of a pinkish, brownish tan.

Some makers have alternated red and beige layers in their domes, which I think is cool.

[gjbingham]

Nice find dmun. What a gorgeous oven!


I assume none of the exterior is red firebrick. You never see the firebrick once the oven is done, except in the entryway. If all you're looking for is visually pleasing esthetics for your oven, I'd look more towards your finish. That's why this oven pictured above stands out.

[herrbeckley]

OK. So here is my progress so far. I have decided to try a barrel arch on two piers in order to then support a large hearth slab. I have yet to build up the sides. I am planning on filling the cavity with concrete up to the top of wood forms mounted to the top course of brick. As a total novice, I am terrified that the arch will fail. Any thoughts?

TB