Paula Ogg picked up her granddaughter Betsy McArron at preschool, and brought her home for a snack of ginger cookies and chocolate seed candies.

"Her personality develops daily," said Ogg of the spirited 4-year-old. "I feel very privileged to see it happening."

Ogg is there to enjoy the day-to-day routine, because she lives just up a flight of stairs from her daughter, Katy McArron.

The three generations share a 1950s Edina walkout rambler, but Ogg and her daughter have their own homes with separate entrances. Katy and Betsy live in the garden-level cozy "condo," while Ogg inhabits the generous-sized house upstairs.

It's a win-win, according to Katy. "Betsy can run upstairs anytime she wants to see Granny."

Multi-generational households like Ogg's and McArron's are increasingly common — 57 million nationwide in 2012, double the number in 1980, according to a Pew Research Study.

There are many benefits, from kids helping aging parents to grandparents pitching in with child care, according to social scientist Bella DePaulo, author of "How We Live Now: Redefining Home and Family in the 21st Century."

"Young adults get along better with their parents than generations before them," said DePaulo. "They ask for their advice and want to do things with them."

Shared living spaces also help family members save money by sharing expenses, a big reason the trend accelerated during the recent economic downturn. But it continued to increase during the postrecession years, indicating "there's a real appeal to this way of living," said DePaulo.

Craig Plekkenpol, owner of Plekkenpol Builders, has seen an uptick in remodeling projects tailored to accommodate extended families. "We're doing more additions, repurposing existing spaces and refinishing bonus rooms over the garage," he said.

Close, yet private

Last spring, Ogg gave up a laundry room and storage space to give Katy and Betsy their own space.

The two women's decision to live on separate floors with private entries reflects today's trend of people "expecting a measure of independence and privacy," said DePaulo. But family members still need to discuss respecting boundaries, she added.

Katy and her mother are defining the rules as they go along.

"I've asked her to call first before coming down," said Katy. "But I go up there whenever I want."

Ogg and her husband, Jim, had lived in the Edina rambler with a tuck-under garage since 1991. After he died three years ago, Paula Ogg wanted to stay because he had just remodeled the master suite and built a screened porch.

But it turned out to be a lot of house and yard for her to handle alone. "My husband did everything around the house. He loved to garden and blow snow," she said.

Meanwhile, Katy, a single parent with a toddler, was renting an Uptown condo with no yard. Paula wanted to spend more time with her grandchild; Katy was calling daily to check on her mother.

Suddenly the pieces of their fragmented lives fell into place. Mother and daughter decided to combine their two households under one roof.

"I was tickled to death that she wanted to do this," said Paula. "And I knew it would work."

"It was so symbiotic," said Katy. "We both benefit from the arrangement. I wanted to be close to her, and she's a ton of help with child care."

Although Paula's health is excellent today, if she has aging-related issues in the future, Katy will be only a few steps away.

Small space lives large

For Katy, deciding to live with her mother was a simple decision compared with the next challenge. How would she turn a bare-bones "mother-in-law" apartment into a comfortable and stylish two-bedroom condo? "I also wanted to make sure I would get a sliding door to a patio to make an outdoor dining room," she said.

Brian Nowak, designer and project manager for Sharratt Design in Excelsior, drew up a floor plan with one major modification that became a game changer. He removed a central staircase that led upstairs to Paula's part of the home. This added 400 square feet, for a total of nearly 1,300 finished square feet.

"Taking out the staircase was scary," said Katy, who paid for the lower-level renovation and hired Closure Construction in Savage to do the work. "This was for real."

After the garden level was demolished down to the cinder blocks, Nowak created one big space connecting the kitchen, dining and living rooms. Down the hall is Betsy's cheery yellow bedroom, a shared bathroom and Katy's bedroom, which is outfitted with a walk-in closet and stackable washer and dryer. Thinking ahead, Katy put in a long double vanity in the bathroom, "so it will be easy to share when Betsy is a teenager," she said.

The hickory floors and cherrywood island are a crisp contrast to the white kitchen cabinets in the "great room." Katy, an avid cook, splurged on a tall German Liebherr refrigerator. "It's sexy," she said. "And with an open concept, it takes center stage when you walk in the door."

To maximize the limited space for storage, Nowak added built-ins, such as a cherrywood buffet, a long window seat for toys, and cabinets nestled inside empty walls.

"Brian asked me if I wanted a mudroom or an office," said Katy, a manufacturer's representative who works from home. "I said both." So Nowak devised a mudroom with floor-to-ceiling cabinets off the garage, as well as a niche to hold the "office in a closet." Katy slides over the dining-room chair to work at the desk, and closes the bifold doors when she's done for the day.

For a cost-effective separate entry for Paula, Nowak designed a new staircase, accented with windows, that leads from the garage and up to her home. He put in a mechanical stair lift for future accessibility. Katy's "condo" also was designed with separate mechanical systems, to simplify utility bills and add resale value.

Inside, Katy chose the furnishings, fabrics and accessories, describing her style as "classic contemporary," a stark contrast to her mother's traditional Oriental rugs and wingback chairs. "Now I have a custom home in my mother's basement," she said. "I designed it how I wanted it."

Mother and daughter smartly repurposed the home's garden level so each can live independently — but also together under one roof.

"I hear just enough footsteps upstairs to know she's rambling about," said Katy. "It's comforting."

Lynn Underwood • 612-673-7619