The minimum ceiling height according to the 2012 International Residential Code is 7′. There are exceptions such as basements and sloped ceilings. The information below is based on page 54 of the IRC. All dimensions are based on finished measurements.
- Habitable spaces, including hallways and laundry rooms, must have a ceiling height of less than 7′.
- Rooms with sloped ceilings must be no lower than 5′ and have no less than 50% of the ceiling less than 7′. The knee walls can be no lower than 5′, the space beyond this does not count.
- A bathtub with a shower head must have a ceiling of no less than 6′ 8″.
- Unfinished basements must be no lower than 6′ 8″ with the exception of beams, duct work, or other obstructions which can be no lower than 6′ 4″.