Abstract: The invention provides a method for erecting a building on a construction site. The building is made from components which are pre-fitted for the building and for a container for transporting the components to a construction site. The pre-fitted components can be joined and refitted to allow reuse of the components. The invention further provides a set of components which are pre-fitted to allow construction of a container of one shape and a building of a different shape. The invention further provides a configuration system for configuring a set of components for a building or a container, a container made from such components, and a building made from such components.