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July 6, 2008
The chase: take two

An exercise in hard thinking, mind bending and trigonometry – Russell tries to figure out how to reconstruct the downstairs chase

Russell has spent the last several months constructing an elaborate wooden “sleeve” around the downstairs center pole of our mountain house. This chase covers all of the plumbing that runs from the upstairs to the downstairs through the center of the house. For convenience, Russell constructed a four-foot-square sleeve that aligned with the existing hole in the foundation. He also constructed a larger cap piece at the top.

On June 26, when Gail returned to the mountain for the first time in two months, we both took a hard look at Russell’s handiwork. Gail was already discouraged by the enormous size of the chase (her original vision was that the 12-inch center pole would be the only obstruction to the downstairs panoramic view). As we chatted, however, Russell realized that the current chase had an even bigger flaw: it did not account for a cooktop in the eventual kitchen that would hug the center pole. The angle of the current chase did not match the angle of the kitchen wall.

The angle of the triangular cooktop counter has to match the angle of the kitchen wall (red). Unfortunately, the hole in the concrete – and Russell's first chase – doesn't match this angle

With Gail’s condolences, Russell made the difficult decision to completely dismantle the chase and reconstruct it. He also committed to try to reduce the width of the new chase as much as possible.

There were a few givens that were “must-haves”:

  1. One wall of the chase had to be parallel to the pantry/bathroom wall that would also serve as the kitchen wall
  2. That chase wall had to be 38” wide, to accommodate a cooktop that Gail had already obtained from freecycle.org
  3. All chase walls had to be at least one inch away from any pipe

All chase walls had to be at least one inch away from any pipe – and there were lots of pipes, at various angles and distances from the center pole

Beyond these requirements, we decided to give ourselves more latitude than Russell had used for the first chase:

  1. The chase did not need to be symmetrical around the center pole; it could be “off-center”
  2. The chase did not need to be square or even four-sided

With these new parameters, Russell envisioned an equilateral triangle, with three identical sides. Gail encouraged him to go even further to minimize size. So Russell proposed an isosceles triangle, with only two identical sides. Russell also investigated having soft corners on each of the three angles. In effect, the new chase would be a non-uniform hexagon, set off-center from the center pole.

The new chase (yellow) would be a much smaller isosceles triangle, off-center with rounded corners, matching the angle of the kitchen wall

The planning process was extremely complicated. What followed were several weeks of hard thinking, mind bending and trigonometry. Russell made an elaborate set of diagrams to try to figure out how to make everything aesthetically pleasing, while still fitting – and optimizing – all of the parameters.

Russell made an elaborate set of diagrams, including little cardboard cut-outs of possible chase walls

Constructing the new chase was even more complicated. After a couple of failed attempts, Russell concluded that he lacked the tools to make the exact angles necessary for each of the six sides. Ultimately, he constructed a full-scale diagram (on a scrap piece of plastic sheeting) that he used as a template for measuring and cutting the wood.

Russell constructed a full-scale diagram on a scrap piece of plastic sheeting

Assembling the new chase was the most complicated of all. Because the new chase was smaller than the square hole in the foundation, there was no “floor” to rest the individual wall sections on. The only way that Russell was able to install the chase was to fasten the pieces together as he constructed them. This way the pieces were able to support each other, while the few parts that overlapped the foundation hole held the whole thing up.

The chase pieces had to be assembled as they were constructed – otherwise the smaller pieces would fall right through the hole in the foundation

Finally, Russell installed scrap pieces of wood to support an eventual sub-floor on the bottom, as well as to attach the structure to the glu-lam beams on the top.

On top, scrap wood fastens the chase to the glu-lam beams. On bottom, scrap wood fastens the chase to the center pole plumbing sleeve. Additional scrap wood creates a foundation for the future sub-floor

Amazingly, the whole thing worked. As we hoped, you can’t tell that the chase off-center because the center pole is completely hidden. You can’t tell that it’s non-symmetrical because you can only ever see two sides of the triangle at once.


The old chase compared to the new – a much less-obstructed view

Unlike the previous chase, Russell has not pre-designed the eventual top cap piece – he will make that up later. Nevertheless, he considers the new chase to be his best engineering feat to date – and that’s saying a lot, considering some of the mental and physical gymnastics that this house has required so far.

Three panoramas of our view – chase-free, the old, and the new


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