Straw Tech

When Anders Stokholm asked hisold friend Felix Jerusalem to design his family’s new home in Eschenz, a northern Swiss village on the Rhine River and Untersee Lake, the client and architect agreed that they didn’t want to disturb the ancient Roman artifacts buried in the property’s wet soil. But they did want something both modern and green. Jerusalem’s solution, the Strohhaus, beautifully merges the old with the new: The structure floats above the saturated ground on pilings—–referencing building methods used in the area thousands of years ago, according to Zurich-based Jerusalem. And except for its concrete core, the entire house is made from slabs of prefabricated, formaldehyde-free compressed straw.

The Strohhaus is no earthy adobe or old-school straw bale dwelling, though. Its walls are made from panelized strawboard sandwiches. Highly dense outer layers perform the load-bearing function, with lighter-weight layers in between creating thermal insulation; midweight slabs were used for interior features.

Compressed straw is a better insulator than timber, Jerusalem notes, and no more flammable when compressed to this degree. It’s also a much more renewable resource: Compared to the years it can take for a tree to mature, straw replenishes in about three or four months—–the time it takes to grow a field of grain. Not much less than the time it took to construct the Strohhaus, which was completed in 2005, just in time for the Stokholms to be settled in for Christmas.

The entire structure is sheathed in inexpensive translucent-green corrugated plastic—–the stuff you’d normally use to roof a small shed—–making the construction and materials visible as well as contributing to the home’s insulation. The unusual outer skin adds an aesthetic bonus when sunlight shines through it, casting shadows in varied patterns across the inner walls.

This transparency pleases Jerusalem, who feels that the raw, exposed design of the Strohhaus contradicts popular associations of plastic and straw with cheapness, disposability, and kitsch. "Andy Warhol took trash and made art out of it; I think this is very similar," assserts Jerusalem.

The €325,000 budget (about $475,000) was tight by Swiss standards, Jerusalem notes, and had to include the intensive research and development involved in prototyping a new design. To stay within budget, the home’s interior is intentionally spare, a "noble carcass," with heating and electrical lines running through exposed pipes.

This simplicity also fits the philosophiesof both architect and client. "I think people should think about how they want to live," says the architect. "Must there always be so much luxury? Could it be simpler and more direct?"

Jerusalem saved more money by concentrating the plumbing—–kitchen, bath, and toilet—–in the concrete core, which extends underground just enough to create a small wine cellar accessable through trap doors. 

Despite the home’s modest footprint, the living room feels spacious and light, thanks to the long, bare walls, free of shelving or detailing. Cheerful white and yellow paint on alternating walls emphasizes the room’s width and dramatic height, and a bulbous black fireplace punctuates the space, suspended from the high ceiling on a long stem. On the west side of the living room, three huge sliding glass doors open onto metalwork steps that lead down to the family’s private garden. The color and light weight of the exterior material help soften the division between indoors and out.

The Strohhaus is set on a roughly north-south axis that maximizes the landscape. At the north end, the open living space flows into a gallery situated above the master bedroom; picture windows frame the view of Lake Untersee and the Rhine. The children’s bedrooms are at the south end, on the other side of the concrete core, creating privacy at both poles of the home. The passage between the children’s rooms and the bathroom also contains the family’s library and kitchen storage.

While the Strohhaus has earned a lot of regional acclaim for its innovation, local reaction was mixed. "Americans think Switzerland is cows and cheese and chocolate," says Jerusalem, and some Swiss are the same, preferring traditional representational design (think Alpine ski chalet) to a deceptively simple-looking house set on pilings. But the Stockholm family is happy with the home, which has seen them snugly through three winters. 

Although the German firm that made the compressed straw slabs has since gone out of business, Jerusalem hopes his prototype will advance architecture’s capacity to solve energy and climate problems. "Architecture learns so slowly from technical [advancements]. We must create new concepts and new materials," he says. "It must be more than only aesthetic; it must have more substance."