28 CFR Part 36 Nondiscrimination on the Basis of Disability by Public Accommodations and in Commercial Facilities (2010 ADA Title III Regulations with amendments issued through Dec. 2016)

From ETA's 2010 ADA Pocket Guide, v 2.2:

Alteration. A change to a building or facility that affects or could affect the usability of the building or facility or portion thereof. Alterations include, but are not limited to, remodeling, renovation, rehabilitation, reconstruction, historic restoration, resurfacing of circulation paths or vehicular ways, changes or rearrangement of the structural parts or elements, and changes or rearrangement in the plan configuration of walls and full height partitions. Normal maintenance, reroofing, painting or wallpapering, asbestos removal, [36.402(b)(1)] or changes to mechanical and electrical systems are not alterations unless they affect the usability of the building or facility.