Planning The Final Chimney Install

Quite a bit of work on the Kuma Sequoia stove installation has happened, and now we are down to the home stretch of mounting the final chimney pipe through the roof.

The tricky part of this whole affair is that, due to the way the ceiling mount pipe must be installed, there is a limit to the degrees of freedom, and thus more planning will be necessary before we punch a hole in the roof.

view of the installation area

Here, we have the existing pipe, which is our first constraint. Here are the rest:

  1. The pipe must start at the top of the existing pipe and go to the roof.
  2. It must clear the existing duct work.
  3. A certain amount of pipe must exit through the top of the roof.
  4. We have the ability to bend 30 Degrees twice.
  5. We have 2 sections of 3 foot pipe and 2 sections of 4 foot pipe.
  6. We have a roof mount that can be oriented in 4 ways.

The Remaining Parts

This is what we have left to construct the chimney:

chimney parts

We know that the roof mount must be fixed; but there are 4 ways that we can do it and each way changes the amount of length protruding from the bottom/inside of the roof:

chimney parts

This can be achieved by altering the orientation of the mounting plates, and either mounting the pipe on top of the roof or on the bottom. So what are our degrees of freedom that we can use to finish the pipe install?

  1. We can choose between 3 and 4 foot lengths.
  2. We can rotate the bend of the pipe around the vertical (Z) axis; this will effectively alter the required length, as it moves the fixed top of the bend relative to the slope of the roof, changing the remaining distance.
  3. We can choose the roof mount configuration.

Adjusting the Model

As it turned out, the best solution was to use a 4 foot bend section with the second option for the roof mount. This requires about a 41.5 degree rotation around the pipe axis. It was satisfying in SketchUp to rotate the whole assembly and watch the little mounting pads line up with the inside ceiling:

chimney parts

Now, it's just a matter of dimensioning the intersection and using some construction lines to find where I need to make the center of the roof hole. The easiest will be to reference off of the beam and from the peak of the roof. The hole will be about 14 inches in diameter, so there will be a little "wiggle" room to account for small discrepancies in fitment and alignment.

final dimensions

I'm looking forward to seeing how this plan plays out in real life!

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