How to think clearly about skyscraper proposals.

A new 50 storey building is being planned at Melbourne’s highest point, next to a park called Flagstaff Gardens in the centre city.

The Age newspaper has been running an energetic campaign against tall buildings in the city. [1, 2, 3] We are lucky to have geology that allows for this fight. Some good rock and an absence of fault lines mean Melbourne can host towers with narrow bases that reach for the sky.

If you own the land and want to build on it, why is that a public issue? The answer is externalities. Building a tall tower there is going to affect a lot of other people.

Rather than throwing around emotive comparisons to New York and Hong Kong as though people are unanimous about whether these places are abominable or admirable, it is worth breaking down the external effects of skyscrapers so we can think about how to balance them.

POSITIVE

1. Increased density.

Great for the buzz of the city. Lowers the effective distance to a bunch of destinations.

2. Lower infrastructure needs.

It is taken as a given that Melbourne’s population will rise (the only policy lever state government could use to prevent that is refusing to permit more building, and thereby making property prices sky-rocket. Which would cause even more trouble). Better to put the people near the jobs rather than out in Dandenong and have to build them a freeway tunnel. So every tall tower is like a tax cut for the rest of us.

3. Skyline.

From a distance, a busy skyline is a beautiful visual asset. Refer to the header on this blog. (Even if in reality the office buildings are a sort of stonehenge for the druids of drudgery.)

NEGATIVE

1. Shadows.

“The idea of the building form is that it is very skinny with regard to the shadow profile,” according to Architect Callum Fraser, in reference to his 50 storey tower. But everyone who works in the city knows that in winter, when the sun is low in the sky, it is a cold and grey place.

The one saving grace is where skyscrapers reflect some of that sunlight back. The rise of glass coated construction is positive in this sense.

(I’m sure in the past I’ve seen estimates of the value of sunlight in the context of this externality but my Googling has failed me. If you know how to track that down please advise!)

2. Need for wider footpaths

What you gain in road and railway savings you have to pay back in footpath. Melbourne planning guru Rob Adams has already been busy stealing back space to be enjoyed by feet.

3. Wind.

This is the one I’m currently obsessed with. Towers create uncomfortable downdrafts. Anyone who went to the University of Melbourne is familiar with the incredible blast of wind under the Raymond Priestly building. Whenever Melbourne’s newest extension the Docklands is criticsed, people call it windy. (1 2 3 4 5 )

It is possible to retrofit buildings to diminish their wind effect – This company called WindTech has carved out a space fixing the issue

“Developers are also beginning to realise the economic benefits in ensuring a favourable wind environment in areas that involve commercial activities,” they say on their website.

Have I missed anything important? Is the issue bigger than just a list of pros and cons? Comment below…