I was recently having a discussion on Twitter about midrise buildings and architect Dermot Sweeny raised the important distinction between creating "spines" and creating "districts."

What he was referring to with "spines" was the way in which Toronto is intensifying its "Avenues" with midrise buildings. It is a kind of linear form of intensification which almost always means that each building must transition in some way to the low-rise housing that typically abuts our Avenues. This is far less relevant in districts.

We have started to increase housing supply in our "Neighborhoods" through things like laneway houses and garden suites, but in most cases, we are arguably not creating urban districts.

This is of course a touchy subject. But I think it's an important discussion to be having for a number reasons:

• Increasing housing supply is a good thing

• Angular planes and other transition measures make housing more expensive

• Urban places are, I would argue, better defined through districts rather than spines

• Mixed-use (employment) becomes more viable with districts

• Transit infrastructure is better utilized with radial density around its stations

Can you think of any others?

Photo: Old Montrêal (Shot on iPhone)