Two single-family homes recently built in Yellowstone National Park achieved LEED certification partly by using insulating concrete forms (ICFs). Constructed as employee housing by Xanterra Parks & Resorts, Greenwood Village, Colo., which operates the concessions and lodging in several western national parks, these homes were the first Yellowstone buildings to achieve LEED certification. The use of ICFs was directly responsible for more than 20% of the LEED points.
The Quad-Lock ICFs were composed of double-thick panels on the exterior (4¼ inches of insulation) and regular panels (2¼ inches of insulation) on the interior with 6 inches of concrete in between. This configuration resulted in walls with an R-value of 32. Plastic ties are designed to be inset into the foam panels, both to eliminate any thermal bridges and to provide a homogenous surface for cement stucco finishes.
Jim Hanna, director of environmental affairs for Xanterra, stated that the ICFs construction “was able to triple our homes' R-values over standard construction materials, an important accomplishment in the heat-sapping winters of Yellowstone. The ICFs walls are excellent heat sinks that augment the effectiveness of the houses' passive solar design, maintaining a comfortable living environment year-round and minimizing the number of days we have to heat the buildings.”