The invention concerns a method by which premises built without a lift can be provided with a lift which is placed in the stair-well of the property. According to this method, a complete lift apparatus 4 designed for the property in question is prefabricated at the works, this lift apparatus comprising a lift shaft 5 with, arranged in it, door openings adapted to the floor plan of the building, a lift cage 6 mounted in the lift shaft 5 and with guide cables 7 and door arrangements, and driving and controlling equipment for the lift, after which a test run is conducted on the lift at the works. Openings which are coaxial with each other in the vertical direction are formed in the stair-well, the dimensions of these openings essentially corresponding to the external dimensions of a lift shaft 5 intended for installation in the stair-well. Arranged in the floor structure of the stair-well there is a foundation 10 intended to support the lift apparatus. The prefabricated lift apparatus 4, test-run at the works, is transported to the installation site and is hoisted, by means of lifting equipment 11 placed alongside the building, to a position above the opening formed in the roof, and is lowered to a position in which the lift shaft rests on the foundation 10. The lift shaft 5 with guide cables is then anchored in the foundation and at each floor level and the lift apparatus 4 is connected to a drive source arranged in the building and is test-run.