The tight economy has more parents, grandparents and adult children living under one roof and new homebuilders are responding with flexible floor plans that can be customized to meet everyone’s needs. Some 16.7 percent of the U.S. population lived in a multigenerational household in 2009, according to “Fighting Poverty in a Tough Economy, Americans Move in with Their Relatives,” an October 2011 study by the Pew Research Center.”

The unemployed and young adults, hit hard by the recession, are fueling the movement into multigenerational households, said co-author Rakesh Kochhar, though social and cultural issues also play a role. Historically, multigenerational living was at 25 percent in 1914, he said, then declined to a low of 12 percent in 1980.