@Greg Scott nailed it.I will also add that since an ESA is an "accommodation for disability" under HUD, the animal's owner is responsible for any modifications to the home in light of that accommodation (think wheelchair ramp). 

I am assuming making it ADA compliant (wheelchair ramps, etc.) would be a prerequisite. 

Each situation is unique, if they need to make modifications to the property, for example adding wheelchair ramps etc., I look at worst case of what would it cost to roll-back all changes and add that in. 

So the places we all encounter that don't even have a wheelchair ramp at the entrance (at the appropriate incline, etc), even though it would be relatively easy to put in, aren't compliant (envision a storefront set back 10 feet from the sidewalk).

Grandma & Grandpa could have their wheelchairs handy to get down the hall to see the grandkids.

At least partially, but the bath could have a roll-in shower, handles, sans the turn radios for a wheel chair unless I open the door to the living room. 

I am looking for help building a wheelchair ramp for a family member.

Im pretty familiar with home wheelchair accessiblility and how the business operates.

Parking should be ample and welcoming, (small carport roof at entrance for rainy times and wheelchair maneuverability maybe?)

What are you going to tell your wife when the house comes down on you and puts you in a wheelchair?