Friedl Bohm's architectural project became his family home for 40 years.

An architect's project became his family home for 40 years.

From the street, the house at 6335 Plesenton Drive looks like a modest 2-story cottage with sand-colored wood siding, a heavily shaded brown shingle roof and a pointed cupola topped with a weathervane. Leafy trees and foliage surround the house, presenting a wooded backdrop and the illusion that what you see is what you get. Without the three-car garage, there'd be no indication of just how grand the estate really is-6,890 square feet on nearly a full acre in Worthington.

The sellers, Friedl and Jean Clare Bohm, are the original owners. They moved in almost 40 years ago and have since made four additions to the house that Friedl-an architect who worked with NBBJ and now runs his own small firm-designed himself. Friedl, who was born and raised in Austria, describes his design as "contemporary European style," largely influenced by houses in Austria. In 1976, the house on Plesenton Drive was a mere 1,800 square feet. As their family grew to include three children, Jean Clare would prod Friedl to move somewhere with more space. "We'll build it," he'd reply. "Tell me what you want, and we'll figure out how to add it on." And that's exactly what he did.

Follow the steep, wooden steps downhill from the stone driveway to the lush backyard, past the cabin-like gardening shed and lily pond, and the scope of the final iteration becomes clear. Three floors, from the walkout basement to the lofted second level, are lined with floor-to-ceiling windows. A multi-layered deck grows increasingly spacious as it wraps around the far end of the house. Despite the staggered additions, the design is seamless, inside and out. Though there are a few quirks.

The newly renovated kitchen, for example, is one of the latest additions and the farthest room from the front entrance. "How many houses do you see where you walk in on one end, and the kitchen is on other end?" Friedl says. Its orientation, though nontraditional, serves as a conduit to the rest of the house, connecting the open living and dining rooms to-also separate additions-a sunken family room and screened-in back porch as well as the master suite via a spiral staircase. Upstairs, a lofted hallway connects three of the house's four bedrooms (the fourth is adjacent to the living room on the first floor).

By today's standards, the design would be considered environmentally conscious. In the 1970s, it was revolutionary. Friedl designed the house to prevent major excavations of existing landforms. He used natural materials, like wood and stone. Outdoor decks were built around trees. The garage, which replaced the original carport, is cantilevered over the grassy hill below. Rather than uprooting trees and earth and filling the space with concrete, Bohm used concrete pillars and wood decking to build the floor of the garage. Most of the windows in the house face south, allowing for ample natural light-and additional warmth in winter. Full trees block most of the heat in the summertime. Utility costs remain low year-round.

The Bohm house also has historical influences. Alongside the creek that trickles through the backyard is a serpent mound, presumably built by early Native American settlers. Not too far up the street, you'll find Jeffers Mound, a prehistoric earthwork believed to have been built by the Hopewell people for sacred rituals. The Bohm's children often uncovered Native American artifacts while traipsing through the creek and adjacent woods. Once, they found what Friedl believed was a broken ancient grinding stone, which he built into a marble fireplace inside. The detail is subtle, not unlike the house itself.

"We wanted something that becomes a part of the land and doesn't hit you in the face," Friedl says. "It's pretty quiet. It doesn't look as big as it is."