Suzanne and Dan Swisher started looking for a new house a few years ago. With their children grown, they were ready to downsize to a place where they could live for the rest of their lives.

But Suzanne had to visit most of the homes and models on her own. Dan, whose spinal cord was injured in an accident almost 20 years ago and is now in a wheelchair, waited in the car, held back by steps at the door. Even some houses in communities for people over the age of 55 had stairs, Suzanne recalled.

“It was impossible,” she said. “Building a custom home turned out to be our only option, unless we would have bought something older and completely rehabbed it.”

Fewer than 4 percent of U.S. homes have features that ease visits by a person with a wheelchair — an entry without stairs, wider hallways and doors, and a first-floor bathroom, according to a report issued this month by the Harvard Joint Center for Housing Studies.

But with the U.S. population aging, demand for those kinds of design elements is likely to grow.

By 2035, one of out every three households in the U.S. is projected to be headed by someone age 65 or older, according to the report, which described the country as at a “critical point” for planning for their needs. About 17 million households are expected to include someone with a disability that affects physical mobility.

At the same time, 87 percent of seniors surveyed by the AARP in 2014 said they want to remain in their homes as long as possible.

“We're seeing more and more people trying to live at home … and the housing stock has not kept up with that pace,” said Jana Lynott, a senior policy adviser at the AARP who focuses on livable communities. “We need to completely rethink how we're going to provide the amount of acccessible housing.”

Nearly 3 million households did renovations to ease access for the elderly or disabled in 2015, according to the American Housing Survey conducted by the federal government, which added the question that year at the suggestion of the Harvard housing center. That represented about 4 percent of all home improvements, the survey found.

People in the industry said they expect those numbers to increase.

More than 6,000 people have completed a three-day National Association of Homebuilders course focused on aging in place, making it the organization's most popular offering, said Dan Bawden, CEO of Houston-based Legal Eagle Contractors, who started the program in 2001.

Manufacturers also have started designing more stylish versions of items such as grab bars, so the changes are less likely to stand out, he said.

“It's such a humongous market,” said Bawden, who said his firm incorporates those kinds of improvements — which can range from adding a few grab bars to much bigger overauls — into every job it does.

Builder Kiere DeGrandchamp, head of construction operations for Pennsylvania-based High Performance Homes, said he first started thinking about the need for those design elements in the 1990s, when families asked for renovations like showers that are flush with the floor.

Since High Performance Homes started a few years ago, he incorporates them into every home he builds— about 10 a year.

“I decided that I was going to build to that standard,” said DeGrandchamp, who lives in Pasadena. “We build everything to age in place, which means you have the ability to grow into your home.”

DeGrandchamp's design — including no stairs at the front door — helped his model stand out, said the Swishers, who hired him to build a house in Westminster on a lot next door to their son's home. The roughly 2,000-square-foot home incorporates wide halls and doors; light switches and outlets in easy-to-reach places; and a hand-held shower, among other features.

They plan to move into the home, expected to cost more than $400,000, early next year.

Dan Swisher said he'd like to see more builders incorporate such universal design principles into their homes.

“It's something that should be standard, because oftentimes it's not a matter of if, but when,” he said. “You're going to have somebody in the family that is going to have mobility concerns most likely.”

The Swishers are sensitive to the importance of planning for the future and are familiar with the real estate challenges. (Suzanne, 56, is a nurse; Dan, 60, is a real estate agent. They met in 1998 when Suzanne cared for Dan at the hospital after his accident, when a rope swing in his yard snapped. Years later, both his legs were amputated because of circulation problems.)

But many families aren't focused on what may happen as they age, said Timothy Ellis, president of the Forest Hill-based T.W. Ellis contracting firm. With older clients, he said, it makes sense to bring it to their attention.

“It's just really a matter of the contractor asking a little bit more questions regarding long-term plans for them with the existing home and then going from there,” said Ellis, who estimated that accessibility remodels represent about 5 percent of the roughly 100 projects his firm works on each year.

Renovations can be costly.

The Maryland Department of Housing and Community Development has long offered a loan program to older homeowners for accessibility-related improvements. A 2010 state task force on aging prompted the program to add grants, which has helped increase participation, said Jack Daniels, deputy director of special loans.

The department approved more than $900,000 in grants to 44 homeowners over age 55 for renovations in the last fiscal year and is on track to sign off on $1.2 million by June, he said.

“Anytime that we can help our citizens stay in their homes, it's going to increase economic impact, it's going to help fix up the community,” he said. “And it's the right thing to do.”

Some states and jurisdictions have explored ways to encourage builders to incorporate the principles, with tools like tax credits or state-verified certifications. Lynott said the AARP supports having standards incorporated into building codes.

It's expensive in the long run to rely on renovations, Lynott said.

“Every bit helps,” she said. “In the long term, we will get more bang for our buck with good accessible design upfront, but given the slow turnover of our housing stock, we definitely need those other types of programs as well.”

Accessible housing is an issue The Arc Baltimore, which serves about 300 people with intellectual and development disabilities in its residential program, struggles with. The agency reopened a home in November that was remodeled to make it more accessible with contributions from the Home Builders Care Foundation of Maryland.

But as its clients age, there is more work to be done — and it's not easy to find new units or secure the money to make needed changes, said Kate McGuire, the organization's chief advancement officer.

“It's definitely a challenge,” she said.

nsherman@baltsun.com