Abstract: The invention relates to the provision of a structure which can be moved from a storage position to an in-use position. The structure is attached to a further building (8) which means that when the structure is moved to the in-use position the structure forms an additional area for the further building. In one preferred embodiment persons entering the further building are required to pass through the structure first, thereby allowing, for example, in a medical environment, the persons to be decontaminated prior to entering the further building.