As American families undergo major economic and demographic changes, the places they live are changing, too. Single-family homes remain the national dream, but behind their traditional facades, a transformation is under way:
* Because contemporary families have much less time for entertaining, dining rooms and formal living rooms are a vanishing species.
* Reflecting the economic change, the time-honored practice of adding extra bedrooms to an existing home is making its way into new-home construction. But separate entrances are common; these rooms are not to house more children, but in-laws.
* The aging of the U.S. population is bringing about other changes in home design -- first-floor master bedrooms with full bathrooms that reduce the need for climbing stairs.
* The rapidly growing number of two-income families and single working parents in apartment complexes is prompting landlords to add in-building child-care centers.
Not that traditional single-family homes, with living room and dining rooms downstairs and three bedrooms up, are on the way out.
But in reality, the number of families fitting the blueprint by which such houses are built -- categorized by the U.S. Census Bureau as "married with children" -- is falling dramatically.
In 1970, there were 25.5 million families with parents and children under the same roof, making up 40 percent of all U.S. households. By 1990, the proportion of these nuclear families in the population had fallen to 26 percent.
At the same time, single-person and single-parent households have grown rapidly, now comprising one-third of the total.
Alongside these developments, immigration by middle-class Asian and Latin American families is on the rise, and their preference for larger homes to shelter extended families is putting different pressures on the housing market.
In a report underwritten by the Ford Foundation, Harvard University's Joint Center for Housing Studies concluded that the impact of these changes, including the aging of the baby-boom generation and an impending explosion of elderly households, has "fundamentally altered the composition of housing demand."
In most areas of the country, according to William C. Apgar Jr. of the Joint Center, the housing needs and demands created by these changes are expected to pump fresh life into the home construction industry.
The redesign trend can be most graphically seen in homes under construction. Builders said the best-selling suburban garrison colonial provides a good example.
In the 1960s, the garrison was a somewhat formal house, marketed to buyers as the next step up from the "starter" Cape Cod cottage and usually featuring a large living room and an architecturally finished dining room.
But today, many builders are replacing the dining or living rooms -- or both -- in their garrison with a big family room, often opening off the kitchen and suited to a contemporary come-and-go lifestyle.