Abstract: A room or like portion of a building, or a complete building, comprises two rectangular tray-like wall elements, at least one inverted tray-like ceiling element, and strip-like floor and wall elements, comprising load-bearing frameworks with cladding. The walltray elements incorporate furniture, fixtures and fittings and together, possibly with others of the elements, form a container of standard size for transportation. The frameworks are provided with lifting eyes which also serve for interconnecting the elements when assembled to form a room or building. Further elements for forming corridor floors and ceilings, cladding, foundation units incorporating service ducting are also transported in containerized arrangements. The wall trays may incorporate telescopic services connections for interconnecting adjacent rooms in a building. Also described are similar containerized forms of elevators, staircases, plant and machinery rooms.