As New Orleans begins to rebuild, architects are taking seriously the question of how to design a home that can avoid being damaged by flooding inside the dykes. One answer is to build the house a buoyant foundation. The design work for this idea is being done by Dura Vermeer in the Netherlands. The key is a concrete foundation that functions both as a basement and as a life raft. It is connected to extendible steel pillars, so that, as the water begins to intrude, the house rises higher and higher with the steel pillars keeping it from floating away. It only floats up. The designers are also thinking of building floating structures for entire blocks of cities, so they all rise above the water together.