by Andrew Getty
Using that extra space in upper levels for habitable living areas having low profile roofs is a popular thing to do. Determining how much area can be used properly will depend on the building design, and how high the roof is.
The New York State Uniform Code, specifically the Residential Code of New York, has minimum requirements for ceiling height and usable floor area.
Although the minimum height of any habitable room is seven feet off the finished floor, it is possible to gain a little more floor area when the area being considered has sloping ceilings that are less than seven feet high.
Straight from the NYS Residential Code:
SECTION R304 MINIMUM ROOM AREAS
R304.4 Height effect on room area.
Portions of a room with a sloping ceiling measuring less than 5 feet (1524 mm) or a furred ceiling measuring less than 7 feet (2134 mm) from the finished floor to the finished ceiling shall not be considered as contributing to the minimum required habitable area for that room.
R305.1 Minimum height.
Habitable rooms, hallways, corridors, bathrooms, toilet rooms, laundry rooms and basements shall have a ceiling height of not less than 7 feet (2134 mm).
The required height shall be measured from the finish floor to the lowest projection from the ceiling.
1. Beams and girders spaced not less than 4 feet (1219 mm) on center may project not more than 6 inches (152 mm) below the required ceiling height.
2. Ceilings in basements without habitable spaces may project to within 6 feet, 8 inches (2032 mm) of the finished floor; and beams, girders, ducts or other obstructions may project to within 6 feet 4 inches (1931 mm) of the finished floor.
3. For rooms with sloped ceilings, at least 50 percent of the required floor area of the room must have a ceiling height of at least 7 feet (2134 mm) and no portion of the required floor area may have a ceiling height of less than 5 feet (1524 mm).
4. Bathrooms shall have a minimum ceiling height of 6 feet 8 inches (2036 mm) over the fixture and at the front clearance area for fixtures as shown in Figure R307.1.
A shower or tub equipped with a showerhead shall have a minimum ceiling height of 6 feet 8 inches (2036 mm) above a minimum area 30 inches (762 mm) by 30 inches (762 mm) at the showerhead.
It seems over the last few years that this has been a common way to obtain more living space.
It seems to be popular not only in new structures, but in existing structures as well.
The Code is fairly liberal on the basic criteria, allowing the use of some floor area not having a full seven feet of clearance.
For those that have been around for a while, note that the minimum ceiling height is seven feet [7’], not seven and a half feet [7.5’].
This was a change in the Code for 2010. See… the code doesn’t always get stricter and stricter…