I have been thinking about this darn chimney since day one and have been dreading its arrival because I honestly did not know how it was going to work. Almost anyplace I looked I found inadequate instructions and missing pictures. I was pretty much lost when I started today, but it came together in its own sort of "just do it" kind of way.
One thing I struggled with was the integration of a clay flue pipe. I originally thought I would get an 8x8 flue pipe, and bring the side bricks (the ones on top of the granite slab) in 1-inch each course until it is the 8 inches apart I want. In order to do this however, the chimney will have just as much height in bricks stepping in as it will flue pipe. So this got me to thinking, do I really need a flue pipe? With a little research, I decided that I did not need a flue pipe. The whole purpose of it would be to prevent mortar corrosion which will eventually lead to a weakened chimney. To keep the story somewhat short, I am not worried about this. I will just make sure to clean the chimney every once in a while and it will be fine. Thinking about it, if the mortar which the flue is protecting is subject to corrosion, so is the mortar between all the bricks below the flue (the ones stepping in an inch with every course). So if the upper mortar joints (now unprotected in my new plan) would corrode, so would the bottom mortar joints (unprotected regardless of what plan you use). Therefore, if I ever for some reason need to replace the chimney (which I don't think I will have to) it would be because the bottom and top bricks alike have corroded... so why even protect some of them if it is not possible to protect all of them. Also, gases from wood are not as corrosive as gases from coal. In conclusion, I am no expert and may be missing something important, but this is where my logic has taken me. No clay flue liner for me!
Phew... now the chimney is a lot easier, but I am now approached by my next problem I have been wrestling with from day one. How do I start the back wall of the chimney on those slanted dome bricks which are coming towards the door? Even if I cut the bricks so that the first course of the chimney can be vertically level, the pressure will be pushed down and in. Ideally, you only want the pressure to go down. Once downward pressure is coupled with inward or outward pressure, it can be asking for trouble. But once again, I am probably being paranoid, especially since this is what it shows in The Bread Builders (inadequately in my opinion). So I am left to my own innovation. So I will just let you see the pictures and end this rambling.
Each course comes in one-inch
In between the third and fourth courses, I decided to put in this metal rod. The purpose is to hold in the back wall of the chimney from wanting to push in towards the doorway if the mortar does in fact ever weaken.
Before proceeding up further, it is wise to brace the bricks, especially if you have to whack the next course of brick to get it level. I actually got to the fourth course and had to start over because the first course lost its bond... I was evidently too rough on it and did not let each course properly set before moving on.
All four courses in place.
I cut pieces to fit the slant, leaving room for a mortar joint at the bottom of each one, and bringing it to the same level as the fourth course. These upright bricks will lean on the metal rod.
You can see here the shape of the bricks that fit on that slant.
This is what I set out to accomplish today. This wall is the front part of the frame in which we will pour the concrete cladding to (hopefully tomorrow).
This is the base of the chimney - it is just straight up from here.
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