To be built in a national park like the National Mall, the foundation for LEAFHouse had to meet the restrictions of limited site disturbance. Indeed, leaving a light footprint on the sites on which we build is a responsibility of sustainable design.
The LEAFHouse design team sees this restriction an opportunity. The first layer of our foundation is composed of reclaimed railroad ties used as cribbing, allowing us the flexibility to level our house on slightly irregular grades without the use of mechanical devices. The design also lightens the house's footprint on the site by spreading the weight of the house over a wider surface area than mechanical "point" support alternatives.
The keys to transferring this weight to the cribbing are the two steel hoisting beams running the length of the house. Necessary for transporting the house to the National Mall and its future owner, these beams also allow us to use a 9-1/2" dimension in our floor framing, due to the reduction in span length between bearing points.