Public accommodations are places like restaurants, hotels, retail stores, professional service offices such as doctors and lawyers, health clubs, day care centers, etc. These types of businesses are required to make their goods and services available to and usable by people with disabilities, which often means making architectural modifications. The ADA defines commercial facility as private sector, non-residential, and involved in any commercial activity. This encompasses factories, warehouses, corporate office buildings, and any other facility in which employment occurs. Many commercial facilities have areas which fall under the requirements applying to public accommodations.
Examples are buildings with employment offices, credit unions, or medical departments.
Requirements for barrier removal in public accommodations apply to these types of spaces in commercial facilities. The general perception is that the ADA mandates that commercial facilities must comply fully only with regulations for new construction and alterations. Note that routine maintenance such as reroofing, painting, asbestos removal, or changes to building systems are generally not considered alterations by ADA definition. Understanding the ADA's definition of primary function will help clarify this potentially confusing rule. Mechanical rooms, employee lounges, locker rooms, corridors, and restrooms, among other things, are not areas containing a primary function.