ADA guidance for private homes

Start with the scope, because contractors get this wrong in both directions. ADA Title III applies to "businesses, including nonprofits, that serve the public" and to commercial facilities. Your parent's house is neither. No inspector will require ADA compliance in a single-family home, and no contractor can honestly tell you the ADA makes you do anything there. If a salesperson says otherwise, that's a sales tactic. Separately, multifamily housing has its own rules under the Fair Housing Act and state and local accessibility codes - different law, different scope, and worth asking a local code official about if you're in a condo or apartment.

That said, the ADA dimensions are genuinely useful, and using them as a target costs nothing. They were derived from measured human factors research and they have been stress-tested across millions of buildings. When a contractor proposes a 30-inch door because "that's what fits," the ADA's 32-inch minimum clear width gives you a specific, defensible number to push back with. Clear width is measured between the face of the door and the stop with the door open 90 degrees - which is why a 32-inch door slab does not produce a 32-inch opening.

The numbers worth memorizing, all from the 2010 ADA Standards as explained by the U.S. Access Board: doors 32 inches minimum clear (§404.2.3), thresholds ½ inch maximum and beveled above ¼ inch (§404.2.5), door hardware mounted 34-48 inches above the floor and operable without tight grasping, pinching or twisting of the wrist (§404.2.7, §309.4), opening force 5 pounds maximum on interior doors (§404.2.9), turning space a 60-inch circle or a T-shaped space 60 by 60 inches with 36-inch arms (§304.3), clear floor space 30 by 48 inches (§305.2), and reach ranges 15 to 48 inches unobstructed (§308).

Where residential work should deliberately depart from the ADA is in the bathroom. The ADA's water closet clear floor space is 60 by 56 inches (§604.3.1) - that is a public restroom stall, and demanding it in a 1950s five-by-eight bathroom will produce either an impossible bid or a bad remodel. The right move is to take the ADA's principles (a clear approach, a reachable grab surface, a seat height that supports a sit-to-stand) and apply them at the scale your house allows. Meeting a standard is not the goal. Someone using the bathroom safely without help is the goal.