Article No: 193

2006-10-04 07:24:42
Found in Translation
By: Carole McMichael



Photography by Cal Rice 


Want to speak Russian, Italian, or German? Your best approach to learning a foreign language used to be living in a foreign country, but some years ago the Concordia Language Villages were established so that language students could study close to home. The Language Villages are the brainchild of professor Gerhard Haukebo, who as a Concordia College faculty member in the early ’60s recognized that the best way to teach Americans a foreign language was to create places for them to live locally that would completely immerse them in a chosen culture. Since the program’s inception, Concordia has acquired 800 acres and has built six villages in Bemidji, Minnesota, in addition to others around the world. The project that began as a summer language camp for kids has moved beyond that, educating students from grade-schoolers to adults.

“All the villages are called Lake of the Woods, but in the native language,” says Stephan Tanner, Intep LLC’s principal architect for the project. “So, for example, the French village is called Lac du Bois and the German village, Waldsee. In Waldsee, most of the buildings still look primarily like traditional German houses. The BioHaus building is an exception, going 180 degrees to the other direction. It shows the leading edge in German building and teaches how modern Germans live. The project is funded in part by the Deutsche Bundesstiftung Umwelt, a German foundation for the environment.” A design planning grant from the Kresge Foundation, Detroit, provided additional funding for the project. 

Besides being part of Concordia’s cultural immersion program, the BioHaus’s main purpose was to serve as an environmental learning center where building technology is an integral part of the curriculum. It models designs and techniques that showcase the advances in green and sustainable building, using German materials and products—many of which, though designed in Germany, are also produced and distributed in the United States. The design of BioHaus was based on Germany’s stringent Passivhaus standard, which meant the building was to be as efficient as possible and use as little fossil fuel energy as possible.

Intep, LLC, located in Minneapolis, Munich, Germany and Zurich, Switzerland, is a consultant for building high-performance, multimillion-dollar projects. BioHaus was more of a pilot project for the firm. According to Tanner, they do “wild stuff” with concrete in commercial applications, so concrete and rigid insulation were a logical choice. They chose an ICF system to make the building structurally sound, energy-efficient and sustainable—with very little maintenance. The ICF they chose was Amvic, which uses expanded polystyrene beads for its foam from BASF, a German company. The Amvic system also came highly recommended by Rehau, another German manufacturer and a sponsor of the project.

BioHaus design
“The style of BioHaus is contemporary—a fairly straightforward rectangular structure, two stories with 5,200 square feet, meant to blend well with the surrounding woodlands,” says Gary Brown, director of marketing and sales for Amvic Building Systems, headquartered in Toronto, Canada. “The first story projects from a sloping hill much like a walkout basement, but it functions as the entrance level. This level is built from Amvic ICFs, with an exterior finished in stucco. It houses the 16 student bedrooms and a large dorm-style shower and bathroom. A common room, studio, kitchen, staff living quarters, a large storage room and three mechanical rooms are on the second floor.”

The walls are on average 10 feet, 8 inches, though some are as high as 12 feet. They are 21 inches thick, combining 5 inches of expanded polystyrene foam, 8 inches of poured concrete and 8 inches of stucco. The structure’s high-tech windows, made by Euroline, are flush with the outside wall. Interior walls use traditional forming techniques and are finished in drywall.

 “The windows were manufactured in a small shop in the Black Forest area,” says Doug Pearson, Zetah Construction’s project manager for BioHaus. “They are large windows; one is 26 feet wide and 12 feet tall. It was made in three pieces, sent by ship, railcar and truck—and installed with the help of the builder who flew here from Germany.”

The windows are part of the building’s passive solar advantage. Bedrooms face the lake and allow students to rise with the sun. Upstairs, the common rooms, teaching spaces and dining areas face south, extending access to daylight and warmth in the winter.

One of the more unexpected aspects of the BioHaus design is its “green” roof. It is a standard truss-joist roof made in the United States and in Germany, covered with an 80-mil membrane and a second membrane, which were covered by a fabric that holds water and lets it flow out. A special soil was deposited on top to grow moss. This helps to keep the roof cool and to recycle rainwater, making even the roof environmentally friendly, according to Brown.

Fitting the standard

Radiant-floor hydronic heating is part of the energy efficient use of concrete. In the BioHaus, it was installed in the basement slab and the first-floor ceiling. The 16 inches of foam beneath the slab keep the heat from dissipating into the earth. Tubing is stapled on top of the wood in the first-floor ceiling and covered with 2 inches of gypcrete. There are three heating zones upstairs and two downstairs.

BioHaus incorporates another unusual system called an Earth tube, which consists of a series of pipes buried below frost level. The air intake is about 85 feet away from the building, and travels underground. In the wintertime, the air is being heated by ground temperature and cooled by it in the summer. Through a heat exchanger, about 85 percent of the energy is passed to the incoming air. There is no recirculation—it is 100 percent fresh air. Used air is expelled from the building, making the structure comfortable and very healthy.

“There are also three geothermal wells that connect to a geothermal system, and a solar system that heats the water,” says Pearson. “They power that with solar panels, but have left provisions for a photovoltaic approach in the future.”

Air-tightness goes hand in hand with energy conservation. Using the Passivhaus standard, BioHaus should consume an incredible 90 percent less energy than is permitted by the Minnesota code.

“To get there,” Tanner says, “you have to build an almost airtight building. Gary Nelson, a national expert on airtight-ness, came personally to test BioHaus because he couldn’t believe how low a benchmark we had to achieve. He measured it and concluded it was the tightest building he’d ever measured in the United States.

“Bimidji is located in a climate zone where it gets 40 degrees below zero for a period of time. At the first meeting with the heating contractor, when I mentioned what size boiler we would need, measured in BTUs, he said he puts bigger ones in the houses for ice fishing. A 5,200-square-foot building uses a smaller boiler than his 100-square-foot ice house. That gives you the sense of how air tight BioHaus is.”

The Amvic process
The footings are 12 inches by 28 inches with rebar protruding vertically. After the footings were poured, the 16-inch rigid foam insulation was put down and then the crew poured the 4-inch slab. After about seven to 10 days, they began stacking the Amvic blocks over the rebar. The blocks are 48 inches by 16 inches by 8 inches. They hold full-length polystyrene webs and have molded rebar holders.

“The first floor is completely stacked with all the window and door bucks installed,” Brown says. “All openings for circuit boxes, conduit and exhaust vents that have to go through the outer wall are cut. Electrical wires are added after the pour by cutting horizontal or vertical grooves with a hot knife, putting in wires or conduit to hold wires and covering with foam. The measurement marks help the electrical crew find the areas that don’t have webbing.

“Then the wall is braced and checked for plumb and true before the pour. Laser levels are used for that. The Amvic system includes a metal bracing system to be attached every 6 feet. Strongbacks can be attached to the webbing and footers. Turnbuckles come out at an angle to tighten and realign any wall that is not straight.

“The pour starts at the corners and works in. The horizontal rebar is installed at 16 inches at the top of each stacked course. If necessary, the blocks can be cut anywhere to fit. There are measurement marks on them at 1-inch increments to indicate where the webbing is. BioHaus was designed in such as way that no cutting of blocks was required.

“The pumper crew pours in 3-foot lifts, going slowly around four times. As the concrete is poured, the pumper is followed by a crewman doing the internal vibrating to prevent voids. Normally, a pour is done in one day.”

The second story
BioHaus was to be built with two different processes—ICF on the lower floor and glass siding on the upper floor. At some point, the plans for the second floor were changed. In place of the glass siding, they used 2-foot-by-4-foot aluminum composite panels: two sheets of aluminum with plastic in between. On top of the lower floor ICF wall, the crew installed a wooden ledger, pouring anchor bolts in the concrete, much as they would when installing a wood truss roofing system.

“The second floor is a 2-by-6 wall sprayed full of isonene foam in the stud cavity,” Pearson says. “On the outside, we used vacuum insulation. It is a German product made from an ash and silica, compressed and wrapped in aluminum foil. Then the air is sucked out to make a vacuum, which produces an R-30-per-inch factor and we have 2 inches, so we have an R-60 value insulation. This created a panel that is 2 inches thick, that can’t be cut or punctured. The siding mounts to that. In between panels, we fit another insulation that can be cut. Our screws for attaching the siding go through standard foam insulation and into the wall. We lose a little R-value in between each panel but that is the only way we can attach it.

“We didn’t send any tech reps to the site,” Brown says. “The installer was fully qualified, and we also had a web cam set up so we could see if they ran into trouble. Amvic provides training in house. There are classes on the technology and installation—builders get a manual and do required coursework and a minimum of two on-site learning sessions where they observe and acquire some hands-on learning experience. On their first individual project, we send tech reps to offer support. Distributors also have this training and offer support.

“We also work with architects and designers extensively to bring awareness up through that fraternity. At the American Institute of Architects show, we do architectural training with an architectural information manual that has all the technical data and support materials to make it easy for them to design for Amvic. We also have a web site that we update regularly to be sure we are getting the information to the right people.”

Talking business
In years past, according to Pearson, Zetah was struggling to convince people to use concrete forms, but in the last couple of years, the sales have become relatively easy.

“Minnesota is really turning on to the ICFs because it only makes sense,” Pearson says. “You are insulating against soil temperature. We have done several whole houses out of ICFs, as well as basements. Doing ICFs in the basement really works well—so well that we now offer only ICF basements.”

Brown sees a promising future for ICFs, growing at the rate of 25 percent a year, driven by energy conservation requirements, weather requirements, sustainable building practices and a generally more well-informed consumer network—a trend that translates well in any language.

For more information on BioHaus, visit; for more information on Amvic, visit