The delivery time will depend on your chosen model and how much work is involved in the factory to build the rail to fit your staircase. Generally, stair lifts for straight stairs are installed in under 2 weeks. You may have to wait 4-6 weeks for a stair lift for curved stairs.Ask the stair lift company how long you will have to wait. If it is urgent, some companies can install quicker. Your stair lift will be contructed and tested in the factory, so it will arrive at your home ready to be fitted.t usally takes only 1-2 hours to fit a stair lift to straight stairs, slightly longer to fit a curved stair lift. The rail will be fitted first, then the motor and the seat. It will then be tested thoroughly and you will be shown how to use it.