The invention basically provides for the installation of a curtain wall of a building using prefabricated wall elements of reasonable size provided in the interior of the building, on an existing floor thereof, while construction is taking place. Each wall element is carried across the floor where it is located on a car or cart by means of which it is presented at the edge of this floor, immediately of the outer side of the building and to the front thereof. At this point it is hung on suspension apparatus for movement to its place of installation. While so hung it is fastened to the building at its required location, subsequent to which it is released from the suspension apparatus. The suspension apparatus utilized is preferably a monorail trolley. The wall elements preferably have a post and tie bar construction and are preassembled on an auxiliary frame in a mannner to facilitate their connection to form a curtain wall and in this process to satisfy the requirements for ease in application of sealing and to provide expansion joints. The car or cart employed for transport of each wall element embodies structural means not only to hold a wall element thereon in a secure position during transport but to provide for its manipulation and pivoting to a vertical position for its connection to suspension apparatus.