Do I need to buttress my side walls?

[UtahBeehiver]

The vertical bricks are going to be a inherently weak design with no stagger bond (alternating 1/2 brick/full brick) You will also need to account for the expansion and contraction of the steel chimney inside.

[Adamk]

Oh, ok thanks for finding the photo for me, I see what you mean by the skills required for building something like that. My design is much simpler in a way as I will place the bricks vertical trying to make the circle. I have a slight concern about the stability as the bricks I found are quite small but it’s a risk I am willing to take. If you have any suggestions regarding extra strength in building these bricks I would be very grateful. I will be using refractory mortar that I have lots left and could add more Portland cement and lime if necessary. Today I did a dry run with the first course of bricks..

[UtahBeehiver]

Found the spiral chimney

[Adamk]

Ok, thanks a lot for the suggestions I will look more into it and try to make a decision about the design..

[Chach]

Sounds pretty cool but pretty heavy at the same time pending how far up you go. Yes you would need to buttress the sides for sure.

[UtahBeehiver]

There are a couple spiral shaped chimneys that use standard rectangular bricks in the forum threads. I do not know the links but it is an advance brick construction technique.

[Adamk]

I am planning to build around the ss pipe ( full length photo below ). While researching on the net I noticed that there isn’t a single WFO with a round brick chimney out there, so I was wondering is there a reason for it( complications on building it ) or just a matter of aesthetics?

[slschoming]

I am going to wait before I start building the chimney around ss pipe until I figure out the buttressing. Finally is it ok to use the half firebricks build vertically or shall I look around for normal bricks?

UtahBeehiver He is still planning to build masonry around the SS pipe. I think he will probably still want to buttress, but do you think his buttress walls need to extend all the way out to the front of his arch, or could he get away with stopping at the edge of his hearth? Look at the large picture in post #8 where he has outlined in red.

[UtahBeehiver]

In your original post, you said you were doing a 3 foot brick chimney. Based on the latest picture, the chimney is substantially shorter and topped with a SS chimney. I do not think you need to buttress now unless you feel you need too. The chimney load is substantially less than original envisioned.

[Adamk]

I am not sure how far forward your chimney will be, but I think you will want some more reinforcement under the landing if the front wall of your chimney will be flush with the front of your arch.

I managed as you see from the photo above to make the base of the chimney so that is not completely flush with my front arch cause I wanted to be able to see part of the arch from the side.. regarding supporting it underneath I might figure out something but maybe it’s not entirely necessary as most of the weight is landing inside the hearth.

[Adamk]

Ok so do you think i can use the same firebricks to build these two extra walls in the sides ?( as I have some already ). And is it ok to build the line of bricks from half way backwards only ?( see photo ), because the rest of the structure is protruding in the front by half brick almost.
When I placed the last layer of bricks that support the arch I had this idea of putting some brass small rods inside for extra strength ( I hope that won’t be a problem with the difference in thermal expansion. Now I have the flue gallery and chimney base ready ( very similar design to the one of UtahBeehiver, thanks by the way for the great and detailed photos you shared of your amazing work ). I am going to wait before I start building the chimney around ss pipe until I figure out the buttressing. Finally is it ok to use the half firebricks build vertically or shall I look around for normal bricks? As David s points out the porosity is not such a big problem, maybe just the fact that they weigh more than normal clay bricks that’s all I can think of.

[UtahBeehiver]

If you were just install a 6" ss chimney, I would say you were okay not buttressing the side walls of the arch. That said, masonry chimney weight add us quickly and the configuration of the outer arch will see substantial sideward loading where the arch and vertical walls meet. You can accomplish buttressing by adding another vertical course butting up against the existing arch.

PS I moved the thread to the oven building section.

[slschoming]

The porosity of firebricks can vary quite a bit. I did a 24 hr soak and weigh on my firebricks and compared it to some solid reds I also had. The porosity measured exactly the same. It could be less of a problem than you think.

Good to know!

[slschoming]

Gulf and UtahBeehiver are both Member Moderators and may be able to help you move your post to the appropriate section. They may also have some good advice on buttressing.

I am thinking that adding one brick thickness would be sufficient buttressing, but you may need to pour a little bit of support under the landing and where the new outer walls will rest as it looks like your landing is hanging off the edge of your hearth. I am not sure how far forward your chimney will be, but I think you will want some more reinforcement under the landing if the front wall of your chimney will be flush with the front of your arch.

[david s]

The porosity of firebricks can vary quite a bit. I did a 24 hr soak and weigh on my firebricks and compared it to some solid reds I also had. The porosity measured exactly the same. It could be less of a problem than you think.