Subsection (a) shall not be construed to require the installation of an elevator for facilities that are less than three stories or have less than 3,000 square feet per story unless the building is a shopping center, a shopping mall, or the professional office of a health care provider or unless the Attorney General determines that a particular category of such facilities requires the installation of elevators based on the usage of such facilities.
42 U.S. Code § 12183. New construction and alterations in public accommodations and commercial facilities
(a) Application of termExcept as provided in subsection (b), as applied to public accommodations and commercial facilities, discrimination for purposes of section 12182(a) of this title includes—
a failure to design and construct facilities for first occupancy later than 30 months after July 26, 1990, that are readily accessible to and usable by individuals with disabilities, except where an entity can demonstrate that it is structurally impracticable to meet the requirements of such subsection in accordance with standards set forth or incorporated by reference in regulations issued under this subchapter; and
with respect to a facility or part thereof that is altered by, on behalf of, or for the use of an establishment in a manner that affects or could affect the usability of the facility or part thereof, a failure to make alterations in such a manner that, to the maximum extent feasible, the altered portions of the facility are readily accessible to and usable by individuals with disabilities, including individuals who use wheelchairs. Where the entity is undertaking an alteration that affects or could affect usability of or access to an area of the facility containing a primary function, the entity shall also make the alterations in such a manner that, to the maximum extent feasible, the path of travel to the altered area and the bathrooms, telephones, and drinking fountains serving the altered area, are readily accessible to and usable by individuals with disabilities where such alterations to the path of travel or the bathrooms, telephones, and drinking fountains serving the altered area are not disproportionate to the overall alterations in terms of cost and scope (as determined under criteria established by the Attorney General).