A growing trendsees adult children and elderly parents living comfortably under one roof.

Central Ohio home builders are seeing rising demand for floor plans designed for multigenerational families looking to live under the same roof, especially ones in which elderly parents can be part of the daily lives of their adult children and grandchildren.

It's a trend that makes a lot of sense to Mark Vouis, a vice president at Trinity Homes. The Columbus-based company sees two or three buyers a month looking to build homes that will accommodate them and their aging parents. Demand is so great that Trinity has some floor plans offering a multigenerational design as a standard option.

“It allows them to have the flexibility of their mom and dad helping with their children and them helping mom and dad when they need it as opposed to a retirement home or assisted living,” Vouis says.

More and more Americans have adopted that outlook. A 2016 analysis of census data by the Pew Research Center found that a record 60.6 million people, or 19 percent of the US population, lived with multiple generations—a household with either two or more adult generations or one that includes grandparents and grandchildren—under one roof in 2014. That was up from 51.5 million Americans in 2009.

While part of that increase was due to more young adults living at home with their parents, more than a fifth of those ages 55 and up lived in households with multiple generations under one roof. In addition, the Pew analysis found that 26.9 million people lived in three-generation households—grandparents, parents and grandchildren.

Central Ohio home builders say some buyers have an immediate need for so-called “in-law suites,” while others are planning for the day when it will make sense to have their elderly parents living under the same roof.

“We're building homes that have bath rough-ins and features for future growth,” says Kevin Yates, a vice president at Powell-based Manor Homes, which has seen increased demand for first-floor in-law suites in recent years.

Manor's entry in the 2016 Parade of Homes at Verona in Powell was a good example. It featured an area with a first-floor bedroom and private bath that was furnished as a family retreat space. The idea, Yates says, was for the space to be used as an in-law suite down the road.

The floor plan appealed to MaryChris and Damon Williams, who decided to buy the home for their family. MaryChris says their parents are in good health, so they don't need an in-suite at this time. But they like the idea of having a space available if the need arises.

“I'm an only child,” she says, “so my parents can live with us if something happens. This gives them their own space that's separate from us. It's all wheelchair accessible, so they would be able to function perfectly.”

The in-law suite also comes in handy when their parents and other out-of-town guests visit. Additionally, the home includes a separate area with a playroom for the Williams' two young children.

“The way they built the house works for our family,” she says.

Manor and other builders offer multigenerational floor plans ranging from a bedroom and bathroom separate from the main living area to ones with full kitchens, living rooms and laundries. Builders say adding an in-law suite typically drives up construction costs by about 10 to 20 percent—a sizable investment when you're talking about homes with prices that start at around $350,000.

But some buyers are willing to foot the bill because of the costs their aging parents would face at an independent living or assisted living community. Monthly fees at such facilities can range from $1,500 to $6,000, according to the American Senior Housing Association, while continuing care retirement communities may also levy entrance fees of $100,000 or more in addition to monthly charges.

In some cases, older parents partner with their adult children on multigenerational homes, says Ed Snodgrass, a vice president and partner at P&D Builders in Delaware.

“That way,” he says, “the kids can buy a little more house because mom and dad put $200,000 or $300,000 into the project. They can build a nicer home and help take care of their parents, too.”

That extra cost depends on the amenities in the in-law suite. For example, P&D is building a home in the Galena area that has two complete kitchens, two laundry rooms and a master suite for the older parents in a multigenerational family.

“You're doubling the amount of the most expensive components of the house,” Snodgrass says. “But most people don't do two complete kitchens. They're doing a nice bedroom, a walk-in closet and living room.”

P&D has seen a definite uptick in interest in multigenerational floor plans. Snodgrass chalks it up to older buyers wanting a home where they can “age in place” or younger ones wanting a house where they can live comfortably with their elderly parents.

He and other builders say multigenerational homes seem to be most popular with ethnic families. That is especially the case with families from India and Asia where multigenerational housing is widely accepted.

In addition, home buyers who have immigrated from abroad want in-law suites that can be used by visiting parents who often stay for extended periods, says Zenios Michael Zenios, owner of 3 Pillar Homes in Lewis Center. They are also popular with buyers who relocate to central Ohio and want separate quarters for their out-of-town visitors as well as with homeowners who just want a first-floor guest suite that is separate from the rest of the house.

“As a design-build company, we're getting a lot more requests for the multigenerational concept,” Zenios says. “It's inspired by an almost hotel style of living. The idea is to maximize an optimal space so (guests and parents) will be more comfortable and tucked away from the rest of the family.”

Zenios' company sees demand for multigenerational designs that include a sleeping suite with a private bath, sitting area and kitchenette.

“That can move the (price) dial by $25,000 to $100,000-plus depending on what the client's needs might be,” he says. “If the budget is tight, they may repurpose a dining room or study for the bedroom and attach it to a bathroom.”

Besides cost factors, home builders can face space challenges in fitting homes with first-floor living areas for parents and guests on lots in traditional subdivisions.

“As lots get smaller and smaller,” Zenios says, “designers and architects have to get more creative in how they allocate the space.”

Manor Homes' Yates agrees, saying a multigenerational home that fits on an average suburban lot and complies with setback requirements can be an issue for buyers and builders.

“The foundation dimensions are considerably increased when adding first-floor living space for aging parents,” Yates says, adding the good news is the trend of eliminating formal dining rooms in new builds has helped provide the space for a second master suite on the first floor.

Jeff Bell is a freelance writer.