Building Green

Green Features of Gilsland Farm’s Environmental Center

There is nothing revolutionary or complicated about the technology or materials used in Gilsland Farm’s environmental center.

In fact, they are extremely simple, and it is in its simplicity that the building can serve as a realistic model for incorporating green principles in most residential or commercial settings.

In siting, design, materials and construction, the award-winning center is a realization of a green future for indoor environments.

Certified Wood

The birch trim, cedar shingles and spruce and fir framing lumber for the environmental center came from Maine woodlands that are certified as well managed. To qualify for this certification, a landowner is subjected to an independent review of the forest practices he or she employs on the land. “Well-managed” means sustaining timber production, maintaining wildlife habitat, protecting watersheds,and recognizing the land’s economic and cultural value to the surrounding community.

Blended Natural Flooring

The colorful floor covering in the environmental center’s kitchen, janitor’s closet and restrooms is Marmoleum™. This petroleum-free product is a blend of wood flour, cork and chalk that is held together with linseed oil, tinted with natural pigments and backed with jute.

Heat from Groundwater

Water from a 600-foot well is drawn to three heat pumps, or compressors. Operating much like a refrigerator in reverse, these pumps extract heat from the 45-50 degree (F) groundwater and transfer it to a closed loop of water circulating through tubing in the floor. Heated up to 130 degrees (F), the circulating water warms the surrounding concrete, which radiates the heat.

Scrapwood Ceiling

The ceiling—or roof decking—of the environmental center is made from lumber castoffs usually considered scrap. By laminating four pieces of this lumber together to form three-inch-thick tongue-and-groove boards, a product is created that is both inexpensive and strong enough to lay directly on the steel frame without supporting rafters.

Insulation Barrier

The formaldehyde-free foam insulation in the environmental center’s walls provides a tight barrier against air and moisture infiltration. Sprayed on the walls in a layer three inches thick, this insulation has an R-value (a measure of its ability to prevent heat loss) of 22—almost twice that provided by an equivalent layer of fiberglass.

Ice-free Roof

Above the environmental center’s roof decking are rigid insulating panels of foamed plastic that are covered by an exterior rubber skin. Manufactured locally and containing a variety of recycled materials—including plastic bottles, film, and newspaper—these panels have extremely high insulation capability (average R-value of 40). By minimizing heat loss, this roof virtually eliminates the possibility of winter ice dams and resulting water leakage.

From Floors to Parking Lot

After most carpeting wears out, it typically ends up in a landfill. But the manufacturer of the environmental center’s carpet has guaranteed to find a better use for it when its days are done. One example is the curb stops out in the parking lot, which the company now makes from retired carpeting. The sticky backing on this carpet both eliminates the need for toxic glues and serves as a radon barrier.

Insulated Glass

Each window in the environmental center is actually two sheets of coated “low-e” glass that lets heat from sunlight enter the building, but restricts its escape. The space between the sheets is filled with insulating argon gas that reduces heat loss through convection.

Fresh Air Ventilation

Energy efficiency depends on a well-insulated, air-tight building, but fresh air is better for human health. To save energy and avoid indoor air quality problems that can lead to “sick-building syndrome,” an air-to-air recovery system uses warm exhaust air to preheat incoming fresh air needed for proper ventilation.

Hydronic Radiant Flooring

Hundreds of feet of plastic tubing embedded in the concrete floor of the environmental center circulate water heated up to 130 degrees (F). The concrete absorbs this heat and provides thermal mass for even warmth across the floor. During the heating season, the air just above the floor is warmer than air at the ceiling—which is exactly as it should be!

Natural Light

The need for artificial light in the environmental center is minimized by the large, south-facing windows and interior glass that allow abundant natural light to reach most of the building for long periods each day. When needed, long-lasting fluorescent bulbs on electronic ballasts provide the artificial lighting. Sensors that detect motion or heat automatically turn lights on or off when people enter or leave a room.

New Steel from Old

Most new steel today contains about 25 percent recycled metal. What’s different about the steel in the environmental center is that it contains more than that—up to 75 percent recycled. The rounded-corner tube steel used combines a familiar post-and-beam look and the strength to span large interior spaces—without cutting any massive old-growth trees.


The long axis of the environmental center faces true south, providing maximum passive solar benefits. Equally important are the many other windows, each of which provides a different view of the outdoor world and its inhabitants—an invitation to go outside and explore.