A Place the Entire Family Can Call Home

Every Thursday, Henk and Elly Oving take care of their young grandchildren. They don’t have to travel far. They just go downstairs.

The Ovings share a five-story home in Amsterdam — two apartments stacked on top of each other and joined by a central staircase — with their daughter Jantien and her husband, Auguste van Oppen.

“It’s two fully independent houses that are intertwined with one another,” said Mr. van Oppen, an architect who could just as easily be describing the 4,900-square-foot home’s two households.

The van Oppens and the Ovings are among a growing number of families sharing multigenerational residences. From Amsterdam to Australia, architects like Mr. van Oppen and his team at BETA, the local firm he co-founded with Evert Klinkenberg, are designing striking homes that make cross-generational care for aging baby boomers and overworked parents as easy as a walk down the hallway.

“It’s about being there together,” said Mr. van Oppen, who designed the home along with Mr. Klinkenberg. “It’s about being there for one another.”

The trick is coming up with designs that incorporate privacy, senior-friendly spaces and flexibility for the future. At the same time, the concept can help address one of today’s more stubborn issues — housing affordability.

Multigenerational homes allow family members to maintain their independence while benefiting from interdependence.

In the 3 Generation House, as it is called, the van Oppens opted for the 1,750-square-foot lower level to take advantage of direct access to the garden for the children, while the in-laws, retired and in their 60s, chose the 1,870-square-foot upper level with an elevator. “We wanted more privacy and the roof terrace,” Mr. Oving said.

Including subtle details like wider doorways and level, uninterrupted floors, their apartment has been designed to be senior-friendly — but discreetly so.

“It doesn’t look like a senior apartment, but it is,” Mr. van Oppen said.

Similarly, in Helsinki, the actors Vilma Melasniemi and Juho Milonoff built House M-M, a three-story home that includes a ground-floor apartment for Mrs. Melasniemi’s grandmother.

“We had long conversations about degrees of privacy,” said Tuomas Siitonen, who designed the timber-clad home, “so they could all live quite close to each other, and the grandparents could take care of their kids, and they could take care of the grandmother, but still everyone could live their own lives.”

The house is on land owned by Mrs. Melasniemi’s parents, who still live nearby in the 100-year-old home where she grew up.

The fully accessible 270-square-foot ground-floor apartment, which was financed by Mrs. Melasniemi’s parents, includes its own entrance and sheltered outdoor space. There is also a common garden area that can be shared by all members of the family.

“When we were building the house, I asked my father to draw the line on paper: Which is the land that we pay for, which is our common space and which is the land of their house,” Mrs. Melasniemi said. “I liked that he made it, as he knows the garden and he knows what he likes to think is their space.”

Mrs. Melasniemi’s grandmother, who was 91 when she moved in, has since died.

“My father got the opportunity to visit and talk to his mother every day,” said Mrs. Melasniemi, who has two children.

But the home is already being used for another phase in its planned long life.

“We discussed the kind of life span of the house,” Mr. Siitonen said. “We thought of how they could use the space when the kids move out, and then when the grandmother passes away. And of course, in the future the parents, one or both of them, might move in there. So it was kind of like we thought of things in five years and 10 years and 50 years.”

As with the 3 Generation House, which was designed to allow for expansions and conversions as the family evolves, House M-M was designed so that the children’s rooms, on the second floor, could be combined. Mrs. Melasniemi and Mr. Milonoff could then move down and turn the spaces on the upper floor into a studio. “And then maybe one of the kids could move into the apartment where the grandmother used to live,” Mr. Siitonen said. “Now it’s rented.”

In Kent, England, Caring Wood is another multigenerational home built with the future in mind. Commissioned by the in-laws of the architect James Macdonald Wright, of London-based Macdonald Wright Architects, it was designed by Mr. Wright and Niall Maxwell, of the firm Rural Office for Architecture, as a country house for the 70-year-old couple and the family’s three daughters and seven grandchildren. “There’s 15 of us,” Mr. Wright said. “The idea really was that we would all spend as much time as possible there.”

Set on 84 wooded acres, the family home takes a pinwheel shape with four corner apartments, one per family.

These are connected to the home’s common spaces, including a central inner courtyard where a family tree cast in glass by the artist Colin Reid sits in the center of the courtyard’s shallow pond.

“Internal walls are all partitions, so they can be reconfigured,” Mr. Wright said. In terms of lifetime use, he said, “there is a lift that gives access to all levels of the house.”

While privacy is built in, Mr. Wright said the children, ages 3 to 17, have no qualms about breaking it down. “They kind of just charge in between all of the individual apartments,” he said.

In Torekov, Sweden, a coastal village north of Malmo, the firm Maka Arkitektur designed a multigenerational weekend home for a mother and the families of her three children, currently including three grandchildren.

“Torekov has always been a kind of generational meeting point for the entire extended family,” said Daniel Hedner, the home’s architect along with Ylva der Hagopian.

Forming an outdoor courtyard that serves as a connecting social space for the family, the 1,740-square-foot home comprises a main building with two wings.

A slightly detached 280-square-foot guesthouse has its own kitchenette and bathroom.

“Access to separate rooms, nooks and corners for privacy are essential in multigenerational houses,” said Ms. der Hagopian, Mr. Hedner’s associate, “as well as generous social space that can gather a lot of people.”

Though large families living together is not a new idea, and mother-in-law apartments are common in many places, purpose-built multigenerational homes are largely “a new phenomena in Western society,” Mr. van Oppen said. But they have a strong tradition in Asian society.

That figured into the thinking of a couple with Asian roots who commissioned Charles House, a multigenerational home in Melbourne, Australia. “For them it was kind of a natural way to have a house,” said Andrew Maynard, whose firm, Austin Maynard Architects, designed it.

For this project, Mr. Maynard turned the traditional Australian “granny flat” (normally akin to a shed out back) on its head by incorporating it into Charles House as an adaptable space on the ground level. Although multigenerational homes are not typically part of Australian culture, Mr. Maynard said the country could certainly benefit from them.

“Sydney and Melbourne are among the top 10 of the most unaffordable cities to own a home in the world. And there’s a whole generation of younger people, millennials, who just can’t even buy into the market,” he said.

Designers and builders have responded to these challenges with a range of less conventional dwellings, including so-called tiny houses. But Mr. Maynard is not a fan of such extreme downsizing.

“I think multigenerational housing is a beautiful way for people to live, if you design it well,” he said. “What I don’t want it to be is another way to basically jam lots of people into a small space. Because nobody’s solving the economic equation of affordable housing” that way.

For Mr. van Oppen and his in-laws in Amsterdam, the only challenge of multigenerational living is the uncertainty of what’s to come. “The challenge is when they get older — how we will organize it,” he said.

Mr. Oving added, “We can’t expect them to care for us 24 hours a day.”

But for the moment, the family is enjoying the benefits of living so close.

“We have dinner together at least once a week, but usually more often,” Mr. van Oppen said. “And we hang out throughout the entire house. So, in the garden, on the roof terrace, in the kitchens.”