-->

High Density Living, 2000 Years Ago: Inside the Roman Apartment Building – Common Edge

The price of living in Rome must have been substantial. A tombstone from a shared tomb outside Rome bears an inscription termed “The Tenant’s Lament” for the ex-slave Ancarenus Nothus. It reads: “My body knows no longer hunger . . . now it is no longer [paying] deposit on the rent, but enjoys for free an eternal lodging.”

As people migrated to Rome seeking opportunities, they would have faced daunting housing challenges. Ancarenus Nothus, who belonged to a lower urban class, likely lived in an insula (Latin for “island”). Insulae were apartment buildings that often occupied entire city blocks and may have risen up to eight stories. Their ground floors typically housed shops, while the upper floors were crammed with cellae—single-room units arranged around a central light well.

Long before the Industrial Revolution brought vertical living, the insulae pioneered the concept of the walk-up apartment. Though their origins remain obscure, a historical record of the Roman historian Livy suggests they may have existed as early as the third century BC. He recounted an unusual event, in which “an ox is reported to have climbed up of its own accord to the third story of a house, and then, frightened by the noisy crowd which gathered, it threw itself down.

Architecturally, the insula may have borrowed certain features from the domus, such as a colonnaded atrium. Like the domus, its entrance was typically a narrow walkway flanked by stores. But besides these more familiar elements, it also introduced innovations: communal staircases, vaulted arcades, balconies, and multifunctional spaces that combined residential, commercial, and even religious uses within a single complex.

The insulae became a lucrative business. Marcus Licinius Crassus, a Roman general and notorious real estate mogul, exploited the city’s frequent fires and building collapses. According to the first-century biographer Plutarch: “He proceeded to buy slaves who were architects and builders,” snapped up fire-damaged buildings from panicked owners at “a trifling price,” and then used his slaves to rebuild them and profit. “In this way the largest part of Rome came into his possession,” Plutarch noted. Crassus was allegedly the wealthiest man in Rome.

Around the same time, the Roman architect Vitruvius championed vertical living. “With the present importance of the city and the unlimited numbers of its population, it is necessary to increase the number of dwelling-places indefinitely.” He recognized that “the case has made it necessary to find relief by making the buildings high.” By having “many floors high in the air,” he noted, “accommodations within the city walls . . . multiplied,” and “the Roman people easily find excellent places in which to live.” Yet Vitruvius also acknowledged the limitations of traditional building materials. “Brick walls, unless two or three bricks thick, cannot support more than one story.”

Structural stability was an ongoing concern. The poet Juvenal lamented: “We live in a city shored up for the most part with gimcrack stays and props: that’s how our landlords arrest the collapse of their property, papering over great cracks in the ramshackle fabric, reassuring the tenants they can sleep secure, when all the time the building is poised like a house of cards.”

“I prefer to live without fires and midnight panics,” Juvenal concluded. “By the time the smoke’s got up to your third floor apartment (and you [are] still asleep), your heroic downstairs neighbour is roaring for water and shifting his bits and pieces to safety. If the alarm goes at ground level, the last to fry will be the attic tenant, way up among the nesting pigeons.”

Fire was an acute hazard in buildings constructed with light wood frames and filled in with branches daubed with mud. As Vitruvius warned, “As for ‘wattle and daub’ I could wish that it had never been invented. The more it saves in time and gains in space, the greater and the more general is the disaster that it may cause; for it is made to catch fire, like torches.”

Enter Roman concrete. Though lime had been used for centuries as a binding agent, such as by the Egyptians, the Romans transformed it into concrete, a standalone building material. By mixing lime with volcanic ash, sourced near Mount Vesuvius, they created a remarkably strong concrete that could even set underwater. Seneca noted, “The dust at Puteoli becomes stone if it touches water.”

By mixing lime with volcanic ash, sourced near Mount Vesuvius, they created a remarkably strong concrete that could even set underwater. Seneca noted, “The dust at Puteoli becomes stone if it touches water.”

This breakthrough allowed Romans to build structures on a scale never before seen. Monumental works like the Colosseum and the Pantheon were made possible—and so too were more resilient, multistory insulae. Builders often paired concrete with...