Micropile foundations offer a sustainable alternative
As an architect who supports sustainability, incorporating “green” is an important part of the design process. Including new landscaping and preserving existing vegetation is critical to the building program. Plantings provide shade, stabilize soils, minimize erosion, cool the environment, support animal habitat, enhance oxygen supply, and nourish the human spirit. This is true for new construction and renovation as well as urban and rural sites.
Saving existing mature vegetation is often less costly and more environmentally friendly than starting with new plantings, but there are design challenges. Tree and shrub preservation require minimizing re-grading and excavation adjacent to the root system and maintaining the water table that nourishes the roots. Micropiles offer a sustainable alternative to conventional concrete spread footer foundations in these circumstances. Micropiles require minimal excavation and relatively small-scale equipment for installation. Micropiles are narrow diameter rods intermittently placed below the building. The slim non-continuous profile does not obstruct the flow of subterranean streams or modify the water table. They also are recommended in areas with highly variable geotechnical conditions.
In this residence designed by Lynn Fritzlen Architect built in 2004, the branches of large old growth trees are within a foot in of the building perimeter. Views from inside the residences are dominated by the conifer forest. The water table rises in the spring to within a few feet of grade and then subsides in the fall to nourish the trees. This home celebrates the old growth trees of the site and nestles the building between them, a treehouse in every sense of the word.