Mother-in-law suite may be real estate shorthand for a second-floor garage addition or a basement remodel, but that bare-bones term hardly covers the extravagant mini homes-within-homes being built in metro Atlanta.

Residences increasingly are required to do double duty to meet the expanding needs of today’s homeowner. A potential rental property or suite for an aging parent can be the perfect option for an unused attic or basement, or an advantageous reason to build an addition. As a bonus to the bottom line, “this additional finished space does add value to the home,” said Sheila Anderson, a real estate agent with Kennesaw Re/Max.

Anderson attributes the demand for in-home suites to the changing needs of the modern family.

“Mom and dad are moving in with their children because of health issues or they have lost their spouse,” she said. “Folks are coming here from other parts of the world and their parents move with them. Also, children are living at home longer these days.”

Letty Hicks Murphy, a partner at Atlanta Fine Homes Sotheby’s International Realty, said clients often seek homes with suites to accommodate live-in au pairs and caregivers for elderly relatives, not to mention the occasional boomerang child.

“In the current economic downturn, many grown children are returning home to live with their parents, and the bonus suite provides privacy and financial savings as well,” Murphy said.

Converting unused space into an in-law suite often serves as a catalyst for creating other usable space for the whole family, said Bernie Smith, owner of MasterWorks Building and Renovation in Roswell. He has seen a trend in clients incorporating not only bedrooms and bathrooms into their renovations, but also kitchenettes, bars and media rooms. The additional recreational space not only helps integrate the aging relative into family life, but also makes the best use of the space.

“I think people realize consolidating their families and moving them all in under one roof is a great financial relief ... and it improves the quality and value of their home as well,” Smith said.

For a recent east Cobb project, Smith took an unfinished basement in a new home and converted it into a multipurpose space featuring a kitchenette, bar, living room with fireplace and billiard room for the whole family, plus a bedroom, bath, walk-in closet and covered patio for the mother-in-law. The result is an addition that greatly enhances the usable space of the home.

“The whole family’s drawn to the basement,” Smith said.

For another project in Johns Creek, the father-in-law contributed some of his own cash to customize a space more suited to his interests. It includes a golf practice room, billiard table, living room with fireplace, media room with game table, a kitchenette and a bar.

Last year Tom Kayler, owner of Kayler Construction Services in Powder Springs, completed a father-in-law suite for Sylvia and Jim Huse of Marietta. Jim Huse’s 72-year-old father, Frank, was relocating from Oklahoma, where he had been living on his own since 1987, and the Huses wanted to give Frank what he’d grown accustomed to: privacy and autonomy.

“[We made] sure he had his own space and he was totally self-sufficient,” Sylvia Huse said. “Yet he has the opportunity to come up and be with us whenever he wants to. We’re coming up on almost a year, and I can’t tell you how lucky we’ve gotten with this. It’s really worked out well.”

Smith recommends clients plan ahead and consider what elderly parents may need as they age. Keeping Frank’s arthritis and its impact on his mobility in mind, the Huses had Kayler create a conversion that includes a wider shower with grab bars, wider doorways, a style of carpet that can accommodate a wheelchair if necessary and vinyl kitchen floors with a handsome hardwood-look that is easier on the elder Huse’s feet and knees.

But the suite isn’t just about accessibility and functionality. Kayler’s top-of-the-line renovation includes a washer and dryer, bedroom, bathroom, family room and office, as well as high-end details such as crown molding, granite countertops and stainless steel appliances in the kitchen.

“All the comforts of home are in there,” Kayler said.

The total cost of a suite is rarely recouped, but based on “Remodeling Magazine’s” Cost Vs. Value analysis of a midrange basement remodel (cost: $57,627; average resale value: $45,757), the return is nearly 80 percent.

Kayler’s in-law suites have ranged from $47,000 to $75,000, depending on size and finishes. If the project is contained within the home’s original footprint, Smith’s suites typically run from $25,000 for bed and bath to $50,000 with a kitchenette. For more features, such as a kitchen, laundry room and media room, prices can climb to $100,000-$150,000, Smith said.

And the demand for suites have remained consistent despite a downturn in the economy. “They’ve held their own ground when everything else has dropped,” Smith said.