High-Density Living, 2,000 Years Ago: What Roman Insulae Teach Modern Apartment Design
Walk through Surry Hills, South Yarra or West End and you'll see Australians wrestling with the same problem the Romans solved — imperfectly but ingeniously — two thousand years ago: how do you stack a lot of people on top of each other in the middle of a busy city without making them miserable?
Ancient Rome had a population of roughly one million people inside walls that would barely contain a modern suburb. Most of them did not live in marble villas. They lived in apartment blocks called insulae — literally, "islands" — that rose four, five, sometimes seven storeys above the street. As Common Edge has documented, these buildings were the workhorses of the Roman city: a piece of typology so durable that you can still trace its DNA in the apartment blocks going up across Brisbane and Melbourne today.
That continuity matters now more than ever. Australian cities are in the middle of a fraught argument about density, design quality and who gets to live where. A look back at the original high-rise might sharpen the conversation.
The insula: Rome's answer to a housing crunch
The insula was born of necessity. Rome's population had outgrown the single-storey courtyard house (the domus) that the wealthy continued to enjoy. Land inside the walls was finite, demand was relentless, and the only direction left was up.
The result was a building type that, in plan, looks startlingly modern. Ground floors were given over to tabernae — shops, bars, bakeries, workshops — opening directly onto the street. Above them sat apartments of varying size and quality, with the best (largest rooms, highest ceilings, closest to the water supply) on the lower floors, and the worst — tiny, dark cells under the eaves — at the top. The further you climbed, the cheaper the rent and the greater the risk in a fire.
Surviving examples at Ostia Antica, Rome's port, show the design moves clearly: brick-faced concrete walls, large windows facing the street to draw in light and air, internal light wells, shared staircases, and a clear separation between the commercial frontage and the residential floors above. It is, in essence, a mixed-use podium building.
What the Romans got right
Three features of the insula stand out as genuinely instructive for anyone designing apartments today.
1. Streets that worked at the ground
Romans treated the ground floor as a public asset, not a private lobby. By renting frontages to shopkeepers, landlords created bustling, walkable streets where you could buy bread, wine and a hot meal within metres of your front door. There were no blank walls, no security gates, no "resident-only" amenity decks. The building paid its rent to the city by activating the footpath.
2. A real mix of incomes under one roof
Because rents rose and fell with the staircase, a single insula could house a modest merchant family on the first floor and a day labourer in the attic. Vertical stratification produced social mixing of a kind that modern Australian apartment buildings — typically pitched at a single price point per project — rarely achieve.
3. Form built around climate, not air-conditioning
Thick masonry walls, narrow streets that shaded one another, internal courtyards for cross-ventilation, and shuttered windows let Romans survive a Mediterranean summer without machinery. These passive design strategies are exactly what Australian apartment designers are being pushed back towards as energy costs climb and NCC standards tighten.
What the Romans got wrong
It would be romantic to stop there. The insula was also a cautionary tale.
Construction quality was notoriously variable. Speculative builders — the Roman equivalent of fly-by-night developers — used cheap timber framing and inadequate foundations. Buildings collapsed often enough that emperors from Augustus to Trajan repeatedly capped their height, first at 70 Roman feet, then at 60. Fires were endemic; the upper floors, served by oil lamps and braziers, were death traps. Sanitation above the ground floor was essentially "a pot and a window."
The lesson is not that density is dangerous, but that density without competent regulation, decent materials and accountable builders becomes a slum. Anyone who has read the report on a leaky combustible-cladding tower in Melbourne or watched a balcony fail inspection in Sydney will recognise the pattern.
The modern echo: density, downzoning and disappointment
The conversation about apartment living in Australia is currently stuck between two poles. On one side is the pressure to build more homes near jobs and transport — a pressure that, as Property Update notes in its outlook for Brisbane, is driving the most sustained run on inner- and middle-ring apartments the city has seen in a generation. Population growth, infrastructure spending and a shortfall of detached housing are pushing buyers and renters into vertical living whether they want it or not.
On the other side is a growing critique of what that vertical living actually looks like. Works in Progress' "The Great Downzoning" argues that much of the developed world spent the twentieth century quietly making it illegal to build the medium-density streets people used to love — the terrace rows, the walk-up flats, the Roman-style mixed-use blocks — and replaced them with either suburban sprawl or isolated towers. The middle, which is where most good urbanism lives, was zoned out of existence.
The Saturday Paper's recent essay "Why are we building a world that nobody wants?" sharpens the point: too much new Australian apartment stock is delivered as investor-grade product — small, dark, mechanically ventilated, lobby-dominated, with retail podiums that read as dead zones after 6pm. We are building density, but not the kind of density anyone falls in love with.
What an Australian insula might look like
Translating Roman lessons into Brisbane, Sydney or Hobart does not mean dressing apartments up with columns and pediments. It means recovering some basic moves.
- Treat the street as the most valuable amenity. Fine-grained retail, food and workshop tenancies at footpath level — not a single 600 m² supermarket lease — are what made the insula social infrastructure.
- Design buildings with a vertical mix. Larger family apartments on lower floors, studios and one-bedders higher up, with shared services in between, can produce the kind of inadvertent social mixing Australian planning rarely manages.
- Use mass and shade before machinery. Narrower streets, deep reveals, cross-ventilation and operable shutters were Roman defaults. They should be Queensland and Northern Territory defaults too.
- Allow the missing middle back in. The "Great Downzoning" thesis is essentially that we have made the four-storey walk-up — the modern insula — illegal across most of our cities. Re-legalising it would do more for housing supply than any tower.
- Hold builders accountable. The Roman experience with collapses and fires is a reminder that height limits and inspection regimes exist for a reason. Density only earns public trust when the buildings stand up.
An old idea worth reclaiming
The insula was not a utopia. It was a pragmatic response to a city that had run out of room, designed by people who understood that buildings are part of a public realm and that the street, the staircase and the shopfront matter as much as the apartment itself.
Two thousand years on, Australian cities are facing the same arithmetic: more people, finite land, rising expectations. The Romans' answer was not a tower in a paddock or a suburb on the freeway. It was a mid-rise, mixed-use, street-facing apartment building, replicated street after street, with all its flaws and all its life.
If we want our cities to feel like places worth living in, rather than places we are forced into, the old island in the urban sea is still pointing the way.