Last night as I was walking home, I came across the recently completed Yonge + Rich condominiums at Richmond and Victoria (I think they won awards for this name back in the day). I stopped to look up because I was curious about one particular detail -- the elbows.

This tower is, in effect, two towers that are attached in middle. And the differing facade treatments are meant to reinforce this: two towers, not one.

But because they are in fact connected, there are some unavoidable 90 degree angles in the floor plates. These spaces can be extremely tricky when it comes to laying out residential suites because they skew your ratio of square footage to vision glass. Usually you get too much of the former relative to the latter. You can also get awkward facing / privacy conditions.

And so these spaces are often referred to in the industry as the "elbow" suites or sometimes the "armpit" suites. Though I think elbows are a lot nicer than armpits.

Here's the Yonge + Rich example to illustrate what I'm talking about:

In this case, the entire stack is comprised of frosted translucent glass. So it is pretty clear that these spaces are not residential suites. Here's the floor plate:

What was done here was to make it circulation/corridor space. This solves the elbow suite problem and adds a nice feature to each floor. These days, very few corridors have natural light. Vision glass is too precious of a commodity. You could argue that it should have been clear glass, but presumably frosted glass was used to avoid privacy concerns.

The other trade-off that needs to be considered is that of efficiency. What is the ratio of saleable/rentable area to gross construction area? Adding circulation space lowers this number. So it can come down to whether it is better to have a higher efficiency with some elbows, or a lower efficiency with no elbows.

Every building is a prototype, isn't it?