A recent University of Florida study, published in the Journal of the American Planning Association, shows the overarching importance of designing homes that are accessible to all potential future residents, regardless of physical ability. The study predicts that by 2050 more than one in five single-family households—21 percent—will include a resident with a physical disability that makes walking and climbing stairs difficult.

The odds increase to 60 percent over a dwelling's lifetime (averaging between 75 to 100 years), through changes in ownership. The study also found that 7 percent of households will include someone unable to get around without help by 2050. According to its authors, "Aging and Disability: Implications for the Housing Industry and Housing Policy in the United States" is the first study to estimate the probability that a newly built single-family home will house at least one person with limited mobility over its lifetime.

Universal accessibility "is something that people just don't think about, because they look at the near term," says the study's lead author, Stan Smith, director of the University of Florida's Bureau of Economic and Business Research. According to Smith, designing homes to be accessible from the outset is important even for those who do not have physical limitations for several reasons.

First among them is visitability (accommodating visitors). "Even if the homeowner doesn't have a disability, they may have visitors who do; aging parents, for example," Smith says. Also, he points out, many day-to-day household activities can be much easier to manage in a house designed for accessibility with features such as zero-step entries and wider doorways: for example, moving baby strollers in and out, carrying groceries, or moving furniture.

Short-term disabilities and injuries are another important reason homes should be designed for accessibility, according to Smith. Accidents happen, and getting around a standard house on crutches or in a wheelchair, even temporarily, can be very difficult. Universal design helps maintain both short-term and long-term livability of a home.

The good news is that most elements of universal design can be incorporated into homes invisibly if they are designed in from the beginning, making them integral to the overall aesthetic as well as to comfort and convenience. Any additional cost to do so is minimal, say the experts.

Universal design goes far beyond the minimum requirements set by the Americans with Disabilities Act, according to certified aging-in-place specialist Rebecca Stahr, founder of Atlanta-based LifeSpring Environs, a residential supportive environments consulting, marketing, and design firm. "It opens up accessibility to everyone, regardless of age or ability. In the trades we like to call it 'good design,' because anything that limits accessibility or any specific group is exclusive design," she says.

To ensure universal accessibility in a home, Stahr recommends covering the basics first—providing at least one zero-step entry (1/2-inch high or less); 34-inch-wide interior and exterior passageways; a full bedroom and bathroom on the main level with enough maneuvering room for two people and a wheelchair—then adding other features of universal design.