A three part foundation system for supporting a building is described. Three part foundation systems can include a containment vessel, which constrains a buffer medium to an area above the containment vessel, and a construction platform. A building can be built on the construction platform. In a particular embodiment, during operation, the construction platform and structures built on the construction platform can float on the buffer medium. In an earthquake, a construction platform floating on a buffer medium may experience greatly reduced shear forces. In a flood, a construction platform floating on a buffer medium can be configured to rise as water levels rise to limit flood damage.