Fair Housing Act says that a loft may contain a secondary living space such as an additional bedroom, den or play area, and the illustration shows an elevated floor area that is reachable only by stairs.
CBC Chapter 11A though, says that an accessible route must connect all rooms and spaces of the dwelling unit, which implies that a loft would have to be reachable by a wheelchair lift, residential elevator, etc.
Do you know of a section in Chapter 11A that would permit an additional bedroom in a single-story, covered multifamily dwelling unit that was reached only by stairs?
Fair Housing Act Design Manual, Chapter 4, page 4.7 Because a loft is an intermediate level between the floor and ceiling of the unit, it is not considered a second story. Therefore, a dwelling unit with a loft is a single-story unit covered by the Guidelines. Since all primary or functional living spaces must be on an accessible route, secondary living spaces, such as a den, play area, or an additional bedroom are the only spaces that can be on a loft unless an accessible route can be taken to the loft.
CBC 1130A.1 General. An accessible route shall be provided through all rooms and spaces of the dwelling unit. The accessible route shall pass through the primary entry door, and shall connect with all additional exterior doors, required clear floor spaces at kitchen appliances and bathroom fixtures. For the purpose of this section, “accessible routes” may include hallways, corridors and ramps.