In the high-end housing market, the traditional mother-in-law apartment over the garage is all grown up. Indeed, some of them these days are bigger than an average main house. They’re guest cottages, retreats, poolhouses-on-steroids. But whatever their owners choose to call them, they’re beautiful, spacious, functional free-standing additions to the properties on which they sit. A leader in the building of guest houses locally is Peter Leeke of Kingswood Custom Homes, who wryly observes that “typically someone who can afford (to build) a guest house is not someone encumbered by the economy.” Leeke has built a range of the structures around Charlotte. One of those was a 1,000 square-foot cottage adjacent to a main house in Foxcroft – which happened to be Leeke’s own former residence. For Mark Lewis of HM Equity Management LLC, who purchased the property, the project “started out as a normal pool house overlooking the garden and pool,” he recalls, “but then we decided to add proper quarters for guests.” The bottom floor has a changing room as well as a fully-equipped gym that takes advantage of natural light from over-sized windows. Guests staying in the studio apartment on the top floor may come and go from a private side gate. The guest house, which Lewis designed himself, cost $250,000 and added the same estimated value to the property. Since its completion, however, he and his wife have decided to downsize and listed the property for sale – asking price $1.975 million. Pools often drive the decision to build a guest house – homeowners want something more than just a place to change into a bathing suit. For Cindy Walsh, the guest house Kingswood built for her and her husband earlier this year behind their house in Stonegate was designed to provide privacy and convenience for guests, particularly “parents with failing joints who now don’t have to climb stairs.” Walsh, a Realtor, and her husband Jim, an investment banker, have moved eight times in Charlotte since 2000. “Our needs have changed over the years, but we’ve always had a pool. A couple of houses ago I realized I didn’t want to have wet people traipsing through the house on the way to the bathroom. We frequently have out-of-town guests who aren’t up at the crack of dawn like we are – with a 6-year-old and a dogs.“So we added something cozy and practical that’s ideal for a weekend but not necessarily for a month,” Walsh laughs. The 450-square-foot house next to the pool is primarily one large open-plan room with a vaulted ceiling, a breakfast bar and a changing facility on one side. Its cedar-shaker roof and taupe-colored stucco exterior finish mimic the main house.A guest cottage can also be a dignified way to provide care for aging relatives. That played into the 1,800-square foot retreat Stephanie Rauch had Kingswood build in 2008 in the woods behind her home in The Sanctuary near Lake Wylie. “I was prompted to build it when I realized my parents were getting older and might need more care. Going into a nursing home was one option, but I wanted to give them other options about where they spent the rest of their lives.“Aging is a painful process, and I knew I wanted to help them all I could. They didn’t want to burden their children, but in their generation, children took their aging parents in, no questions asked. I’m trying to figure out how I want to age, and their situation resonated with me,” says Rauch, a mind-body therapist.Her mother has since died, but her father comes to visit from time to time, “though never often enough,” she says.So her “home away from home” has become primarily “a place to relax and work on my inner self,” Rauch says. “It’s in this incredible setting surrounded by woods, with a huge (200-square-foot) porch.” It is furnished on the same high-end scale as her main residence, which she bought in 2006.Up at Lake Norman, Joe Grainda of Grainda Builders in Cornelius has recently launched a custom guest house project. The owners envision this 700-square-foot lakefront guest “casita” – a Spanish term common for cottage in their native Arizona – as in-law quarters featuring a living room, kitchenette and master suite. Its exterior will complement that of the 8,000-plus-square-foot main house, now also under construction. Not far away, Spivey Custom Homes of Mooresville built what is arguably the granddaddy of local guest cottages ¬- a $1.4 million waterfront structure overlooking Lake Norman. It contains 3,450 square feet including a two-car garage.The property owner, who is based in Florida but travels extensively as an international business consultant, built it in 2008 as a place to stay while the main house was under construction, as well as a gathering place for his adult children in years to come. The 25,000 square-foot main house was completed in November 2010.Builder Willis Spivey describes the French country-style guest house as “magnificent but comfortable” – a house that says “come on in.”It’s a phrase that is echoed at every guest cottage, large or small, that builders have completed around the region – after all, its purpose is always to make visitors feel welcome.