Case Study: Metal Lark by SALA Architects

It’s a special kind of building that embraces its surroundings in all seasons, especially in the cold North. The ideal for every weekend getaway is to blur the distinction between exposure and enclosure, but to turn that kind of architecture into a comfortable rental takes a skilled architect and a particularly adventurous client. Both were on hand in the making of Metal Lark, the first in a handful of eco-friendly structures that will sparsely populate a 140-acre site. Once used as farmland swapped between corn and soybeans, the property had been converted to a meadow filled with prairie grass and wildflowers.

This wasn’t the first time builder Kevin Fossum worked with the owners, having previously built their retreat house close by. They are a retired couple who live an hour and a half away in the Twin Cities. They went in on this business venture with their son, whose affinity for Pacific Northwest architecture led him to David Wagner, AIA, formerly of Seattle, who built a house he admired near his own Minneapolis home. Those connections helped the team to coalesce quickly around the big decisions.

The first was where to build the house. The owners were intent on a tower-like structure, and the site offered many possibilities. One was a lovely hillside with a territorial view of the lake, but it had no physical connection to the shoreline. The team also explored a steep wooded bluff before selecting a spot along a tree line. “Over decades, a farmer will put a barbed wire fence in and trees start to grow along the edge,” David says. “Thirty or 40 years later a line of trees marks the landscape as an artifice of this old fence line.” On this unique edge where the land dropped away to the lake, “we sensed we could create a nice approach for vehicles, park on one side of the trees and create a short path through them to the tower. There’s almost a threshold experience of passing through the tree line to get to the house.”

One of the hallmarks of Pacific Northwest architecture is large expanses of glass to bring light inside on gray days. Deep overhangs protect buildings from rain, and here they would be needed to offset rain, snow, and sun. The Northwest is also known for architecture that expresses structure, and for warm modernism rooted in wood construction. 

This scheme ticks all those boxes. The 35-foot-tall tower sits on a rise on the east edge of the oaks, maples, and ash, which provide a windbreak and shade the building from the low western sun. Canted southeast for better solar exposure and lake views, its 20-by-20-foot footprint consists of two levels plus a half-level on the ground for storage and mechanical equipment. Visitors enter over a bridge at the middle level containing a mudroom, bedroom, and bath. The bridge continues straight through the building to a cantilevered viewing platform on the opposite side. Upstairs, the top floor is one large open space for the kitchen, dining, and living area. Folded into a cabinetry wall, a double bunk pulls down to accommodate extra guests.

Shell Game

The tower’s transparency and cantilevers called for steel framing, but “steel and cold temperatures don’t go well together,” David says. The team developed a steel exoskeleton that was custom-fabricated by Northshore Steel on Lake Superior, which was then infilled with wood-framed wall, floor, and roof systems. While three glass walls on the second and third levels create a spectacular perch from which to gaze over the land, Cor-Ten steel acts as a wind brace, wrapping the northwestern entry side and portions of the side walls. “The idea was to create something durable,” David says. “It became this nice shell that feels almost like the building is a full glass cube from outside, with this warm coat that slips around it to protect it. The angles provide a little extra dynamic expression—a tall, outward thrust—as the hillside drops away.” The Cor-Ten wall assemblies are 12 inches thick and packed with insulation to ward off winter’s prevailing winds. 

To achieve the floor-to-ceiling glass, David was able to spec residential windows rather than a pricier curtain wall system. “We could get away with it because of the wind bracing we did to the exterior out of 2×4 Douglas fir, running from the floor plate to the ceiling framing to create a strong back fin that braces the windows,” he says. Punched window openings in the Cor-Ten steel are fitted with zinc sheet metal casings that pop out and repel weather. The same treatment occurs on the front door, tipping out to mimic the shape of the Cor-Ten shell. One Cut Construction’s crew forklifted the heaviest, 700-pound windows into place and built the industrial-style roof. 

Viewed from across the meadow, the house becomes almost an abstraction, its simple geometries flattening to two dimensions. David chose a structural corrugated steel roof deck to achieve a thin edge on the left and right roof cantilever. “Looking at the roofline from the ground up, you see the galvanized heavy metal soffit and 3×8 fir beams that cantilever out in a pretty large overhang,” says One Cut’s owner, Kevin Fossum. “The roof sandwich consists of LVL beams exposed on the inside, topped with 3×8 fir timbers going the opposite direction and spray foam, then perpendicular 2x3s. On top of that assembly is the galvanized steel edge that you see on the soffits, three-quarter-inch plywood, and a rubber roof with tapered foam to create a slope.” 

Warm Modernism

A snug variation of this aesthetic reappears on the interior finishes. These are simple and durable, befitting a hard-use rental: black slate tile on the mudroom floor; Sheetrock walls; Douglas fir cabinetry, window frames, and exposed rafters; and white-washed, engineered oak flooring with radiant heat. 

A relief from the glassy façade, punched windows open unexpected sightlines. Stairs to the main level ascend behind a canyon of cabinetry and emerge into the bright upper space. An interior window at the kitchen sink provides a view through a high exterior window on the stairs. “You can look out and see who’s arriving in the driveway,” David says. Another window at the entry brackets an outdoor view from the staircase. 

The stair acts as a cooling tower, with operable windows and ceiling fans drawing out hot air. “We’ve done as much as we can to make this project sustainability driven,” David says. In addition to the passive strategies, a bank of solar panels in the meadow behind the building supply roughly two-thirds of the power needs.

“Both the homeowner and the architect had a lot of good ideas,” says Kevin. “Between the three of us, it turned out really well.” The various short-term tenants seem to agree. According to David, the owners’ business venture has been “wildly successful” so far. “It’s booked out as far as they want it to be,” he says. “Open dates fill within hours.” Part house, part viewing platform, its integration of industrial and organic, indoors and out, elevates the experience of shelter.

Metal Lark

Frederic, Wisconsin

Architect: David O’Brien Wagner, AIA, principal in charge, SALA Architects, Minneapolis

Builder: Kevin Fossum, One Cut Construction, Grantsburg, Wisconsin

Interior Designer: SALA Architects, Minneapolis

Consultants: Northshore Steel, Two Harbors, Minnesota; D.P. Juza Woods + Fixtures, Shell Lake, Wisconsin

Project Size: 900 square feet

Site Size: 140 acres

Construction cost: $575 per square foot

Photography: Gaffer Photography

Key Products

Cladding: Cor-Ten Steel, VMZINC, Richlite

Cooking Ventilation: Zephyr

Cooktop/Oven: Bosch

Countertops: Caesarstone

Dishwasher: Bosch

Doors/Windows: Loewen Windows

Faucets: Hansgrohe

Fireplace: Jotul

Flooring: BOEN, Daltile

HVAC system: Warmboard-S

Lighting: Vista Light, MP Lighting, WAC

Refrigerator: Whirlpool

Sinks: Ruvati, Duravit

Toilets: Kohler

Ventilation: Panasonic