7. Doubled up
Separate self-contained living units are appearing in some new homes. They're essentially in-law suites, either inside the main house or attached to it, often with a separate entrance. At the minimum, these include a bedroom and adjoining bathroom. Some have a small living area and kitchen or kitchenette.

The demand for these houses is complex. By 2010, 16% of Americans were living in multigenerational homes, according to the Pew Research Center. The census, looking at the picture slightly differently, last year found 30% of adults in "doubled-up" households that include adults besides students, spouses and partners.

Reasons for this new closeness include cutting costs and desire to be nearer to family members. Immigrant cultures — particularly Latino and Asian – are a market force and bring traditions of including several generations under one roof.

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At the same time, as the elderly live longer, many adult children are bringing their parents into their homes, often motivated at least partly by the need to contain elder-care costs. A 2011 poll (PDF) by Harris Interactive and Generations United, a group promoting intergenerational collaboration, found financial stress driving much of the trend.

"In the past, the solution was to put a casita (a little house) over the garage. And if grandma wanted to use it, she had to walk up stairs," Thompson says. Moving the casita into or alongside the house makes life easier for everyone.

It's hard to judge the strength of demand. A surge in construction of dual master suites in homes, predicted in a 2007 NAHB member survey, hasn't materialized — probably because of the extra expense, Melman says.

However, the market for new and old homes with ADUs (accessory dwelling units, a planning term) is strong, says Matt Wakefield, spokesman for Redfin, the online realty company. Redfin buyers mostly want them as rentals, for supplemental income. All three of Builder Magazine's showcase homes at the National Association of Home Builders' International Builders' Show in February include ADUs.

"I've been doing show homes for 15 years, and I don't think we've done this," Thompson says.

The suites are more easily financed in higher-end homes. Tim Walker, whose DreamBuilder Custom Homes in Tigard, Ore., targets the upscale market, built one of six homes with ADUs in a "street of dreams" project last year.

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Those houses, finished in August 2011, were priced from $800,000 to $975,000. Five sold immediately and the last, Walker's, closed in January.

"That tells you, yeah, there probably is a big demand for ADUs," Walker says. 

Pulte Homes offers casitas in new homes in the Phoenix area that are priced from $500,000 to $600,000. And Lennar Homes' NextGen four-bedroom, three-bath homes include a "private living suite" with a secure private entry, kitchenette, living area, bedroom and bathroom. Prices vary, but in Bakersfield, Calif., 2,257-square-foot NextGen homes start at $257,990.

8. Filled with storage
Builders are listening to buyers who have been asking for more storage for years, Thompson says. With fewer rooms, more storage is a big selling point.

One feature that hasn't been stripped out of many new homes is the walk-in closet in the master bedroom, Melman says.

Also, new homes often have utility rooms off the garage and second-story laundries filled with cupboards, closets and shelves, Thompson says.

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