To varying degrees, multigenerational household have always been a fact of American life.  Over the last couple of decades, however, the numbers have been creeping up. According to the Pew Research Center, in 2008 some 49 million Americans, or 16% of the total U.S. population, lived in a family household that contained at least two adult generations or a grandparent and at least one other generation. That’s a significant increase from1980 when the figure was about 28 million, or 12 percent of the population.

See also: Grandchildren as caregivers.

And there’s reason to believe that the Great Recession is accelerating that trend even further.  According to Pew, the number of multigenerational households rose by 2.6 million between 2007 and 2008 alone.  In 2009 an AARP poll found that 11% of people age 50 and older live with their grandchildren or their parents, and 11% of those ages 35-44 report living with their parents or in-laws. And my hunch is that those numbers will continue to grow.

I'm meeting more and more grandparents who move in with their adult children because they have lost a job or because the stock market's fall has dashed their retirement dreams. And I hear from just as many grandparents who tell me their adult children and grandchildren are moving in with them because of job changes or home foreclosures.

There’s a lot to be said for different generations living under one roof.  In addition to the financial aspect, both young and older people reap lots of benefits from sharing space.  It’s great for kids to get some extra-special attention from loving grandparents. And older people report feeling less isolated when they live around children and grandkids. Young adults, too, experience a sense of safety and security when they move back “home” with their parents.

Next: Ways to keep the peace in your home. »