Method for retrofitting a building using a lift system and component kit for performing the method

A method for retrofitting a building with a lift system, the building containing a plurality of stories (3) which are subdivided and have story doors (4) which are accessible via a common staircase (5), the staircase (5) being adjacent to a front side (1) of the building and, for each story (3), having a main landing (7) for the story doors (4) and an intermediate landing (8) for a double-flight of stairs (9),

• the method comprising:
• prefabricating the lift system (26) having a shaft (27), having a cabin (36) which is movable in a longitudinal direction of the shaft (27), with guides and drive elements, and a lift platform (35) for bridging a distance between the cabin (36) and the building for each story (3), the shaft (27) extending over at least two stories (3) and comprising a self-supporting sheet metal box made of at least one steel plate, which is provided for receiving the cabin (36) together with the guides and the drive elements, said sheet metal box extends in a straight line in the longitudinal direction of the shaft (27) while being profiled in a cross-sectional plane orthogonal to the longitudinal direction of the shaft (27), and the sheet metal box of the shaft (27) having a cross section which forms a cross-sectional area in the cross-sectional plane within the sheet metal box, the cross-sectional area containing an area required by the cabin (36) and the guides and the drive elements and additionally an area of the lift platform (35),
• fabricating a foundation (14) for the lift system (26) in front of the front side (1) of the building,
• opening the front side (1) of the building in a width direction of the staircase (5),
• removing the intermediate landings (8) and the double-flight of stairs (9),
• installing walkways (24) at a height of the main landings (7), which extend horizontally from the main landings (7) to the front side (1) of the building and thereby only partially cover the cross section of the staircase (5) to provide clear space for a flight of stairs,
• installing a single-flight of stairs (22) which connects the individual walkways (24) to one another and forms a modified staircase therewith,
• setting up the lift system (26) on the foundation (14),
• aligning the lift system (26) on the foundation (14) and joining the lift system (26) to the front side (1) of the building,
• establishing a connection between the lift platforms (35) and the walkways (24) on each story (3), and
• establishing access to the lift platform (35) of the ground floor from outside the building.