When John Salmen invited me to see the Takoma Park, Md., house where he and his wife, Ann Scher, “expect to spend the next 50 years,” I wasn’t sure what to expect. As both Salmen and his wife are already more than 50 years old, the house would eventually have to accommodate a person facing the frailties of advancing age.

Would this be the centerpiece of the design? After all, Salmen has spent his architecture career specializing in barrier-free design that accommodates people with disabilities.

The answer was a resounding no.

Salmen has a playful manner, and so does his house. Nothing in it says “a place I can live when I’m frail and 90 years old.” Instead, most visitors will find it to be a delightful renovation of a 1900’s bungalow with a newer addition on the back.

The exterior of the house conforms to Takoma Park’s historic district requirements and looks similar to the other modestly-sized, clapboard-sided, Craftsman-styled bungalows with front porches. The Craftsman-styled interior, however, is unique to the neighborhood. It features a color palette that is historically authentic but unusual in its hues and strong contrasts — cobalt blue, pumpkin orange and light-cream yellow.

The heart of the 3-bedroom, 2, 000- square-foot house is the eat-in kitchen/family room, which occupies the entire first-floor area of the new addition. In keeping with the Craftsman-styled interiors, the space features abundant amounts of clear-stained cherry trim around doors and windows, an exposed beamed ceiling, strategically placed cherry clad columns that hold it up, and multiple windows on three sides that flood the area with natural light.

Of greater interest to me, however, were the numerous, nearly invisible ways in which Salmen designed the main living area to be flexible, not in the sense of “multipurpose” but in “accommodating disabilities.” Cloaked in a Craftsman aesthetic, almost every detail has been masterfully designed to help this couple navigate the shoals of old age.

Although neither spouse is disabled, Salmen’s years of designing for disabled people have made him acutely aware of how to modify a space so that an older person can comfortably “age in place.”

Many of Salmen’s design subtleties address diminished vision, which begins to affect almost everyone in their 40s and 50s and becomes much more pronounced as we reach our 80s, said Mariana Figueiro, a professor at Rensselaer Polytechnic Institute in Troy, N.Y., and an expert in lighting issues for the elderly.

In choosing the color scheme for his main living area, Salmen went for bold contrast — light yellow walls play off against the rich red oak flooring and the darker cherry trim. Today, this contrast creates a visually lively space, but 30 years from now it can help Salmen and Scher to maintain their balance and prevent falls. When walls and floors are the same color — as is commonly the case in traditional senior housing — an elderly person with poor vision may be unable to distinguish between floor and wall, “lose the horizon” and fall, Salmen said.

Strategically placed lighting can also help a person with diminished vision to navigate through a space. The light source does not need to be a fixture. In this case, ambient light shining through a glass cabinet indicates the direction of the main living area from a central hallway.

The abundance of natural light that streams through the 12 windows in the kitchen/family room area will be increasingly appreciated over time. Compared to a person aged 20, a person aged 70 generally needs about three times as much light for tasks that require more acuity such as reading or peeling and chopping vegetables in the kitchen, Figueiro said. The high clerestory openings above the kitchen and living areas provide indirect lighting that reduces glare, another issue for older people with vision issues, she said.

Other details here will accommodate a person in a wheelchair. For example, recessed into a corner, the generously-sized, quarter-circle-shaped dining table backs up against two built-in benches, which Salmen and Scher currently use for dining. When they have guests, they add chairs to the rounded side, which can easily accommodate two wheelchairs because the table does not have table legs; it has a single pedestal support.

The 18-inch level of the raised hearth makes it easy for a person in a wheelchair to operate the gas fireplace. The two large 36-inch-wide by 42-inch-high cherry panels that conceal Salmen’s enormous flat-screened television and elaborate home entertainment system are so light-weight an individual in a wheelchair can easily move them using only one hand or even only one finger, Salmen said.

The counters in the kitchen are set at varying heights to accommodate children, very short and very tall adults and individuals in wheelchairs. For average-height adults, the different counter heights make some cooking tasks easier. For example, it’s much more comfortable to knead bread and roll out pie crust on a 30-inch counter, six inches lower than the 36-inch standard height for kitchen counters, which are too high for most people, said Jane Langmuir, a Providence, R.I. architectural designer who designed the kitchen.

In this kitchen, the counter heights for the food-preparation areas are 33 and 34 inches. The 1.5-inch diameter grab bar in front of the sink currently functions as a dish-towel rack, but its easily graspable shape is ideal for a person in a wheelchair to hold while reaching down to pick up something dropped on the floor or for opening a drawer or lower cabinet.

The everyday dishes and glassware are kept in open shelves only three inches above the counter instead of the usual 18 inches that separate standard wall-hung cabinets from countertops. The lower shelves are an easy reach for the average adult and a godsend for a child, a short person or person in a wheelchair.

Salmen also added touches of serendipity. In working out the Craftsmen details with designer and builder Alan Abrams of Abrams Design Build in Takoma Park, Salmen decided to expose the two steel I-beams that hold up the second floor. This provided an opportunity to display about 50 model houses that he and his now-grown daughters put together “on the innumerable rainy Saturdays of their childhood,” he said.

At the end of the tour, I asked the obvious: What led Salmen and his wife to embark on such a huge undertaking when they were 30 to 35 years away from needing most of the accommodations that they so seamlessly incorporated into their house? Salmen offered two reasons. The first and most compelling was that when their younger daughter graduated from high school they were ready for a “life change and a nice little house,” Salmen said. They decided to make their new house their last house because he knew it would be much easier to organize the project in middle age than if they waited until they were older and the need became more apparent.

In your 60s and 70s, “It’s still doable but daunting physically and draining emotionally because you have one or two more decade’s worth of associations with the house,” he said. “In your 80s, you will very likely need other people to orchestrate everything, an unacceptable option for most elderly people who want to feel that they still have some control over their personal lives,” he said.