It was a typical night at the big house on Victoria Street, which meant that its collection of unrelated adult occupants were engaged in a number of unrelated endeavors.

Michelle Belliveau, 29, whose boyfriend, Bill Finn, 34, owns the Dorchester home, was in the living room, picking through bins of holiday decorations. In the kitchen, roommate Jeff Hoogenboom was brewing beer. And out in the yard, Francis Shiman-Hackett, 35, drink in hand, was contemplating a dip in the backyard hot tub — which, he explained, has become a regular part of his routine.

"In the mornings," he said, "I'll sit here and have my coffee and check my e-mail."

The home and its occupants represent both a complex form of cohabitation and a new normal. All the roommates are in their 30s, or close to it. All are well into their respective careers. And at an age at which the majority of their peers have gravitated toward more traditional living situations — gotten their own places, moved in with a partner or spouse — all have elected to bunk in a manner familiar to anyone who's ever caught an episode of "Friends."

They are part of a small tribe of young(ish) professionals who, according to some local real estate brokers, are increasingly willing to share a living space later in life as a way to offset exorbitant housing costs and ensure a prime location.


"It's been a thing that we've seen the last couple years more than ever," says Adam Mundt, leasing manager at Metro Realty Corp. in Brookline, of 30-somethings sharing quarters. "You just didn't have to do it back in the day — you could find affordable apartments."

National numbers, certainly, seem to back up that assertion. A US Census Bureau report issued in 2013 shows that households with multiple unrelated occupants have risen slowly but steadily through the decades, from 1.7 percent of all households in 1970 to 4.6 percent in 1990 to 6.1 percent in 2012. A 2014 Zillow study indicates an even larger recent jump, putting the number of adults living in "doubled up households" at around 1 in 3, up from around 1 in 4 in 2000.


In Boston, says Barry Bluestone, the founding director of the Dukakis Center for Urban and Regional Policy at Northeastern University, the reason for the shift is simple: Millennials are pouring into the city at a staggering clip. Twenty- to 34-year-olds made up 35 percent of the population of Boston, Cambridge, and Somerville in 2000. Over the next 10 years, that demographic was responsible for 74 percent of the population growth in that area. And unlike their parents and grandparents, they aren't looking to immediately settle down in the suburbs and start families.

"It's a true demographic revolution," says Bluestone. "And it's really fundamentally changing . . . Greater Boston."

Part of the shift, certainly, is born of necessity. Much has been written about Boston's soaring housing costs, and in places like Cambridge, Back Bay, and Beacon Hill — where even studios can fetch $1,800 to $2,200 per month in rent — only the most well-compensated young professionals have much hope of renting a place by themselves.

And it's not just rent, says Brian Kitchens, co-owner of Encore Realty in Brookline. "Utility costs, Internet, food," he says. "It's cost prohibitive to live in Boston."

But throw in a roommate or two — a couple friends, or strangers, for that matter — to help carry the financial load and, suddenly, a new world of possibility opens up.


"I probably wouldn't be able to live in Jamaica Plain if I didn't have roommates," says Laura Golas, a 31-year-old master's candidate at Simmons College who currently shares an apartment with two roommates she found through Craigslist.

Take the house on Victoria. A beautiful and spacious three-story Victorian with hardwood floors and a sizable backyard, the home "was definitely a financial stretch for us," Belliveau says of she and her boyfriend. Which is why they decided to rent out some of the five bedrooms to friends.

Today, there are five people living in the roughly 3,000-square-foot home, a mix of friends who share bills, a TV, and the bond that comes with occupying a living space.

To certain 30-somethings, the appeal of such an arrangement is obvious.

Unlike the messy, dirt-poor days of college roommate situations, arrangements among older roommates tend to be a bit more refined. At the Victoria house, for instance, you'll find plenty of furniture, two well-stocked refrigerators, a butler's pantry that has been transformed into a sizable bar. And forget chores; the income saved by bunking up allows for a professional cleaner.

But more important than common conveniences, say many 30-somethings, is the social component.

"I wouldn't want to have a solo apartment," Shiman-Hackett says, sitting in the living room on a weekday night, as a handful of people bustled about. "It's too socially isolating. It's not how I like to live."

Indeed, the Victoria home boasts a notable familial feel. While the house's occupants are constantly coming and going, they all seem to have at least a general idea of where the others are at any given time. And on the occasion one of the occupants needs something, there's usually someone willing to step in and help.


At one point on a recent evening, Hoogenboom, in the middle of a brewing session, called out to the others, "Do you have any cheesecloth?"

"I do have cheesecloth," Belliveau responded, ducking into the kitchen to look for it.

It's these everyday interactions — as well as a slew of other factors — that can make living with roommates later in life an enjoyable endeavor, says Annamarie Pluhar, author of "Sharing Housing: A Guidebook for Finding and Keeping Good Housemates."

"We've had this idea that if you're an adult and you're single, you should live alone," Pluhar says. "And I think a lot of people are waking up to the fact that that's not healthy.

"People are beginning to think about, 'How do I do this differently?' "

Still, it's far from the norm. The limited figures devoted to tracking the housing habits of 30- to 35-year-olds indicate that those living with roommates remain relatively rare. Additionally, some Boston-area brokers report that while they see plenty of clients in their 20s looking for shared housing, those who've reached 30 are typically more interested in a place all their own — even if it means moving outside the city to places like Somerville, Medford, or Belmont.


"Around 29, 30, once they've passed their first job and they're in a more stable job position, [that's] kind of when they want to be by themselves," says Ranjita Singh, a manager at Cambridge Realty Group.

Like anything, there are inherent downsides to sharing living quarters with others. Lack of privacy, the shared use of common space. The risk of incompatible roommates, like one vegan former housemate of Golas's who threw a fit anytime chicken, or even cookies, were prepared in the house.

But asked whether he and his housemates ever get tired of each other, Shiman-Hackett replies, "We were all [vacationing] in Greece a month ago, and we share the same ski house; so I wouldn't say we get sick of each other."

In some cases, in fact, it's quite the opposite.

Shiman-Hackett's girlfriend, Laura Fawcett, recently moved out of the Victoria Street house and into another place a couple blocks away, which she shares with just one roommate. Though she enjoyed her time at the residence she affectionately calls "the crazy house," she says, she initially welcomed the new home's slower pace.

Since moving, though, she finds herself regularly gravitating to the big place on Victoria. There's always something to do, always someone to chat with. Lately, she admits, she's been spending more time there than at her new place.

"I thought I wanted to get away from it," she said. "But apparently not."

Dugan Arnett can be reached at dugan.arnett@globe.com. Follow him on Twitter @duganarnett.