Beginner with a foundation problem.

[dmun]

Re: Beginner with a foundation problem.

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]

Re: Beginner with a foundation problem.

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

TB

[dmun]

Re: Beginner with a foundation problem.

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]

Re: Beginner with a foundation problem.

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]

Re: Beginner with a foundation problem.

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

[dmun]

Re: Beginner with a foundation problem.

As a total novice, I am terrified that the arch will fail

Highly unlikely If your two side piers are filled (masons traditionally use rubble fill for this kind of thing: alternating layers of masonry junk and wet concrete) there will be lots of lateral support for your shallow arch. I just kept building my brick walls up past slab level: no wood forms needed.

Just mix your mortar as stiff as possible, and wet your bricks before you lay them. You may want to consider the purchase of a tool called the "bricky" Makes bad bricklayers good, and good ones fast (just a satisfied customer, no connection)

[herrbeckley]

Re: Beginner with a foundation problem.

but my arch is not very shallow. In fact it's a full roman arch I believe.
TB

[herrbeckley]

Re: Beginner with a foundation problem.

Also, I think that my photos didn't appear as an attachment in my previous message. Is there anything I need to know other than using the attachment function on the message page?

TB

[herrbeckley]

Re: Beginner with a foundation problem.

Trying the photo again.

[dmun]

Re: Beginner with a foundation problem.

The full arch is even stronger because there is not so much sideways thrust. You should be fine.

[herrbeckley]

Re: Beginner with a foundation problem.

When I finished the third row of the arch, I noticed that the last brick was not tight. I counted the bricks and everything is right. Not sure how this happened. I'm thinking that if it was loose at the top, no matter how much mortar I use to fill in the gaps, it's going to be a weak or failing row in the arch. Is this true?


Also, thanks to everyone for all the help. This project is a lot of fun.

[dmun]

Re: Beginner with a foundation problem.

Welcome to the wonderful world of bricklaying. Unless you are VERY good you are always having to fudge various brick/block postitions. The trick is that not every brick is exactly the same size. (firebricks are better than common brick in this regard.

A picture will help us envision exactly what your problem is.

[herrbeckley]

Re: Beginner with a foundation problem.

Arches fell with a small amount of pressure applied. Back to the drawing board. One thing, the mortar seemed very brittle-chalky even. Upon inspection of the post-failure brick pile, I found that the mortar had hardly adhered to the piers or each other. This cause the bottom bricks of the arch to shift away from the center and the middle to collapse. Comments?

[gjbingham]

Re: Beginner with a foundation problem.

Its really hard to tell what the problem might be because in the photo, there's so much mortar on the bricks that you can't really tell where bricks and mortar start and end.

My best guess is that you put pressure on the arch too soon. Unless your bricks are cut to lock in completely so that there is almost no mortar in the joints between bricks, you need to leave the form and arch alone for a week or so befor you attempt to remove the form and stress the structure.

Hope that helps a bit.

[herrbeckley]

Re: Beginner with a foundation problem.

After a hiatus of eight weeks or so, I'm back at it. How does this sound to you folks. Two concrete filled brick walls spanned by cedar 4 x 4's to form a base. Then a layer of insulation, then normal brick, then hearth floor. Beams span only about 28" and the will be secured flush to one another. I think that the wood will be protected from the heat of the oven and cedar is a tough wood perfect for exposure to the weather. I'm about to get started on this (brick walls are complete), so if this is really stupid please let me know.

My original plan to use the arch for support was beyond my skill level (three collapses).

Very Respectfully,
Tom