Barbara Vanderkolk Gardner and her husband, Tom, fell in love with the duplex penthouse for sale in The Promenade on Longboat Key because of its great light, Gulf views and spectacular sculptured stairway.

But most of the furniture was included in the sale, and it took Barbara’s trained eye to envision the formal interiors in a look she could live with.

“Contemporary but classic is my mantra,” Gardner, president of Collins Interior Design, explains. “I updated the accessories, fabrics, hardware and window treatments, then added rugs and artwork that reflect my style as a designer.”

Gardner also recognized the couture-quality Donghia furniture already in place, and knew she could make the pieces fit her family’s casual lifestyle. “This was a beautiful place that looked tired and seemed a bit formal for the beach,” she says. “It’s always a challenge to refresh, update and personalize a home that’s bought furnished, but I do it all the time in my work.”

Gardner retained Tonya Fischer to repair a custom wall treatment lining the great room and curved staircase: Donghia wallpaper cut into 18 inch squares to resemble Belgian block.

Existing white couture-quality sculptural seating from Donghia was personalized with large decorative pillows from Sarasota Home Collection and accent pillows from Madison Park.

Black granite and white marble floors were dressed down with area rugs that also define conversations areas: a looped Berber from Parker Robinson and sisals from Williams-Sonoma Home.

Donghia’s contemporary Bergere chairs with gilt frames were recovered by Messenger’s Upholstery in animal prints from Boca Bargoons: faux tiger on the front and leopard on the back.

The designer chose ethnic accessories to soften the too-formal setting: a mirror frame of zebra wood over the bar, a wall piece and metal floor vase from Angsana, and tall twisted reeds from The Lamplighter Shop.

Fox Mirror and Glass added a mirror to the bar and halogen spotlights were installed to refract light on eclectic barware collected over the years from Royal Doulton, Waterford and Villeroy & Boch.

From Chasen Reed’s collection of silk flowers and rustic wooden containers, Gardner created her own arrangements for a black console table in the dining area and living room coffee table.