2010 ADA Standards for Accessible Design Pocket Guide
201.2 Application Based on Building or Facility Use.
Where a site, building, facility, room, or space contains more than one use, each portion shall comply with the applicable requirements for that use.
36.401(b) New Construction; Commercial Facilities Located in Private Residences
(1) When a commercial facility is located in a private residence, the portion of the residence used exclusively as a residence is not covered by this subpart, but that portion used exclusively in the operation of the commercial facility or that portion used both for the commercial facility and for residential purposes is covered by the new construction and alterations requirements of this subpart.
(2) The portion of the residence covered under paragraph (b)(1) of this section extends to those elements used to enter the commercial facility, including the homeowner´s front sidewalk, if any, the door or entryway, and hallways; and those portions of the residence, interior or exterior, available to or used by employees or visitors of the commercial facility, including restrooms.