You might want to look into what the ADA requires about building accommodations for handicapped accessibility. Hint: You aren't compliant just by throwing up your hands and saying "We aren't accessible, don't bother", especially not for commercial real estate. I.e. you can't simply discriminate against handicapped people, which is the problem that necessitated the passing of the law in the first place.

Even residential real estate has to follow a bunch of codes though, like secure railings on all stairways for starters.