Amsterdam was recently facing a need to temporarily host collections of National Historical Museum. With an extensive programe of 9000 square meters for only 5-10 years, this task became politically and technically a great challenge. The strategy is therefore based on temporality of space. Most of the building's mass is made of clay and rammed earth which are materials degradable by water. The deflatable roof spans over a building mass with a pipe drainage systems. These are used to control aging of each module. So each module can exist only for the time necessary. By the time the building will not be needed anymore the whole temporary museum becomes a ruin, and eventually dissolves in waters of Het IJ. This concept is also reacting to milions of abandoned office buildings in Holland and envisioning how entropy could be used positively on large scale projects within the building environment.