Dreamer turning to "do-er"

[Blairt]

Put blocking underneath Durock and installed rebar today. I filled several of the CMU holes with rocks to avoid having to fill ALL of them with cement. When I looked at the height of the door opening for the firewood under the dome, I thought that 3 blocks high wasn't enough for comfort. I used 2 pieces of 3/8" angle iron to span the opening. This will be filled with concrete as well.

[Blairt]

Finally starting on the CMU base. With help from my brother, got the first two rows done on Thursday. Finished second two rows yesterday.

[Blairt]

In searching for insulation for under my WFO, I've found a thermal ceramic insulating firebrick TC-23. It is rated to 2300F. Can I use this as the base layer between my concrete pad and my firebrick oven floor? Morgan IFB Datasheet.pdf

[Gulf]

You may need to make sure what the actual code for your area says.

Since I'm under the overhang of our roof, this means that I have to go two feet ABOVE the peak of the roof

You say "over hang". Is that an eave or a gable?. My local code says that I have to be two feet above any structure within 10 feet. For an eave, a level horizontal line drawn from the nearest point from the exit of the chimney to the run of the roof plus two feet above that satisfies that rule for us. Your code may be different, but it is worth double checking.

This will result in a masonry chimney of about 12-13'.

Yes, that's a lot of weight for a chimney that maintains an 8" masonry thickness. Some areas allow 4" of masonry around a flue liner. But, clay liners and 4" of brick still add a lot of weight. A stainless steel liner (single or double wall) will be much lighter. It may boil down to what your code defines as a liner. You may also be able to add a lighter weight 4" ("masonry") around that than 4" thick brick. But, lets check out your codes to see what we can safely do within what your local codes, insurance carrier, and your own peace of mind will allow. If you can post a copy, I might be able to help.

EDIT: Try to go to a larger size pic for your posts. You may need to add fewer pics and use multiple posts to satisfy the forum requirements.

[MarkJerling]

That's going to be quite a bit of weight. The door arch will carry the weight, provided it's buttressed sufficiently. The problem, of course, is: What is sufficiently?
The problem you will have to contend with is "lateral thrust" which will be the mass from the top trying to flatten and push the arch below sideways. There are a few things you can do:

• You can construct your door arch much more solidly than normal.
• You can add further stress relieving arches over the door arch.
• You can have very solid buttressing to the sides of your arch.
• All of the above.

[Blairt]

I've been dreaming of an outdoor kitchen and pizza oven for years. We finally built our retirement home and moved in this past summer. We are on Vancouver Island in British Columbia, Canada. Starting the oven build in our cold and rainy winter isn't ideal but if I choose the times right I think I can get some good progress and be done in time to be cooking next summer.

I've attached some pictures of the base that we built. The buttresses and concrete slab were engineered to support the weight of the oven so I'm quite confident that my base is good. I do have a question on the chimney though. Our local building codes require a full masonry chimney on any wood burning stove or fireplace. I had hoped to be able to use double-wall stovepipe but it will not meet the building code.

Since I'm under the overhang of our roof, this means that I have to go two feet ABOVE the peak of the roof. This will result in a masonry chimney of about 12-13'. My concern is being able to build the door arch and the opening in the base (for wood access) strong enough that I do not have to worry about the weight of the chimney above. I've never seen pictures of anyone building such a tall chimney. How can I build to be confident of the height and support?

In the photos attached, I've tried to show the buttresses and pad. The red outline shows approximate area where the oven will go and the final photo shows how high I have to go with the chimney to clear the roof.