This is one of many articles describing changes between the current Chicago building code, and the updated building code that becomes optional on December 1, 2019, and mandatory on August 1, 2020.
The modernized Chicago building code reduces the minimum ceiling height in residential units. This will have a big impact on existing residential buildings. By reducing the minimum ceiling height from 7'-6" to 7'-0", it may be possible for more people to convert basements and attics to accessory dwelling units (ADU), and have shorter height additions to expand the area of a home. In bathrooms and laundry rooms, the minimum ceiling height is further reduced, to 6'-8".