Abstract: A prefabricated transportable room element for use in the construction of a plural storey building comprising a plurality of such room elements stacked one upon another, the room element comprising a floor panel structure and at least one vertical load-bearing structure extending upwardly of the floor panel structure, the room element having releasably connected thereto structural bracing means which is connectable to the foundation of a building and/or to the bracing means of another like room element when the room element is stacked therewith, the room element and the bracing means having buttressing surfaces which co-operate to transmit horizontal loads on the room element to the bracing means whilst allowing relative vertical movement between the room element and the bracing means when the room element is incorporated in a building with the bracing means connected to the foundation of the building and/or the bracing means of a like room element stacked with the room element and with the bracing means rele