Eleanor Smith, the grandmother of the visitability movement, came to town last week to challenge a group of architects.

OK, I hadn't heard of visitability, either, but Smith set me straight.

Think of it as something that lets her drop by your house. Odds are your door is a little narrow, the steps uninviting. Deal breakers for her.

Smith is a soft-spoken, 67-year-old irresistible force on wheels who has testified in Congress and sat in a street to command attention for the rights of disabled people.

She traveled to Philadelphia from her home in Decatur, Ga., where she lives in an "intentional community" - one where owners of all 67 homes planned their living spaces, giving them wide entrances and no steps, roomy hallways and first-floor bathrooms.

Smith's neighborhood allowed her to go next door and deliver a casserole to a new mother. When volunteers were needed to hand out petitions, she happily raised her hand. These are simple things she can't do most places.

Her goal is to get builders to start thinking about those who have trouble walking on their own. Odds are we'll all be there one day.

At age 3, Smith contracted polio. In the 1940s, Eureka, Ill., had no curb cuts, so the library and the grocery store were not open to her. In her first apartment, the door to the bathroom was so narrow that to get to the toilet she had to crawl.

She taught college-level literature and English as a second language and was working as a social worker in the mid-1970s when she heard an architect say: "Disability is not caused by the physical condition; disability is caused by the built environment."

Those words changed her world.

"I realized that people actually make decisions that let me get into one building and not another," she said. "It's kind of obvious. But it wasn't to me then. I thought, 'If what he says is true, it's horrible and has to be changed.' "

She started reading magazines such as the Disability Rag, an unapologetic advocate for basic rights, and found her voice. "Most disabled people I knew weren't angry," she says. "They were just coping."

By 1984, she was flying to San Francisco to protest buses built without lifts. "Here was this group of disabled people willing to sit in the street, to go beyond ordinary politeness to press a civil rights issue. I was just smitten."

She thought, "If buses have to have access, why not new houses?"

Her first success was convincing Habitat for Humanity. By 1989, each of its Atlanta homes was built with a ground-level entrance and a bathroom big enough for a wheelchair.

To date, 40,000 houses across the country have been built to those specifications. Since most new houses have first-floor powder rooms, the biggest expense is wider doors, which typically cost no more than an extra $110, she said.

In Philadelphia, at least 850 visitable homes have been built since 2006. The architects she spoke to Friday spent the day coming up with designs for new visitable and affordable single-family homes in East Kensington.

Visitability was not Smith's first mantra. The T-shirts that her organization, Concrete Change, used to sell took six words to say what she says now in one: "Basic access in every new house."

Smith could often be seen sporting one of those shirts, which came with the kicker, "Cuz you gotta visit friends and lovers."

"I was younger," she says.

About 20 years ago a visiting Japanese student told her that Europeans used the word visitability, and she immediately liked the term because it took the focus off houses for the handicapped. "It's that whole 'Special houses for special people' thing" - which she hates.

She wants to end the isolation, the segregation, that many immobile people must endure.

"Visitability doesn't say 'my house.' It says 'other people's houses,' " Smith says. "What matters to me is not what it's called. It's that houses are built that we all can enter and live in and age in."

Contact Daniel Rubin at 215-854-5917 or drubin@phillynews.com.