Courtesy Department of Energy
Courtesy Department of Energy

The Mall in Washington became a showcase for building science last month when 20 teams of university students showed off the homes they had built for 2009's Solar Decathlon. A German team won first prize, followed by groups from Illinois and California, while Louisiana's entry won for "Most Viable" and was the people's choice. The competition focuses on energy, but it also reveals creative construction techniques and some notable products. Here's a look at three entries.

Creators of BeauSoleil house, the entry from the University of Louisiana-Lafayette, believe it can be built on a production basis for $120,000 to $150,000. The traditional dogtrot-style house has a twist: Six custom-designed sliding glass doors (from NanaWall Systems) can be moved in several directions to form an interior room, expand one of the two adjacent rooms, or open a breezeway. BeauSoleil generates more energy than it consumes and can withstand hurricane-force winds. Doug Ashy Building Materials was a key supplier.

Team California's Refract House addresses a big issue in the Golden State–conserving water–by having downspouts atop the house direct rainwater to a harvesting pool. In the summer, it dries out to become a rock garden. In the winter, it fills up into a rain garden. Its open joists were made of bamboo, and the redwood weather screen came from fire-damaged stock. Pine Cone Lumber provided materials.

Bamboo provides the framing for the University of Illinois' Gable Home. It's billed as 10 times stronger than traditional timber, so instead of a stud 1-1/2 inch wide, 3/4-inch-wide bamboo could be used. The extra space was filled with insulation. R.P. Lumber supplied many of the building materials.