Urban

The Case for Density: Why Melbourne Should Build Up

Your Name 2 min read

Melbourne has spent four decades answering a housing shortage with more Melbourne — another ring of subdivisions at the urban fringe, another hour added to the average commute. The result is a city that is geographically enormous and functionally sparse. The argument of this piece is simple: the fringe is the expensive option, and density is the affordable one, once you count the costs we have learned not to see.

The hidden bill for sprawl

Greenfield housing looks cheap because its true costs are deferred and socialised. Every new fringe estate draws decades of public spending — roads, trunk water and sewerage, schools, transport — long after the developer has moved on [src-1].

The cheapest house to build is the one at the edge of the city. The most expensive house to serve is the same house.

That gap between building and serving is the whole argument.

What the evidence actually says

The case for density is not that towers are intrinsically good. It is narrower and stronger:

  • Infrastructure costs per dwelling fall sharply with density, up to a point [src-2].
  • “Missing middle” housing — terraces, low-rise apartments — delivers most of the benefit without the downsides people fear from high-rise [src-2].
  • The relationship is non-linear: the first doublings of density buy the most.1

Here the sources disagree. One body of work treats transport emissions as the decisive variable; another argues that construction emissions from concrete-heavy towers can erode the gains for a generation. Both can be true at different densities, which is exactly why the missing middle keeps winning the argument.

A worked example

# Rough per-dwelling infrastructure cost as density rises (illustrative).
def infra_cost(dwellings_per_hectare: float) -> float:
    base = 75_000  # fringe servicing cost per dwelling
    return base / (1 + 0.12 * (dwellings_per_hectare - 15))

The curve flattens fast: the move from 15 to 40 dwellings per hectare captures most of the saving, and you never need a tower to get there.

What should change

Three changes, in order of leverage:

  1. Legalise the missing middle across the established suburbs, not just on a handful of designated corridors.
  2. Price fringe infrastructure honestly, so greenfield development carries more of the cost it imposes.
  3. Protect against the real risks — overshadowing, displacement — with design rules, not blanket height caps.

Density is not a threat to the city Melburnians love. It is how that city pays for itself.

Footnotes

  1. The marginal benefit of each additional dwelling per hectare diminishes, which is why the policy target should be “gentle density everywhere” rather than “maximum density somewhere”. ↩