The actual final rules are here.
https://www.irs.gov/businesses/small-businesses-self-employed/tangible-property-final-regulations
An improvement is characterized as a betterment, an adaptation, or a restoration. I suppose I was lazy in saying an improvement "adds value", but that's a shortcut for "betterment" which is a bit harder to define. @Carl 's example of an in-ground pool would be an adaptation to a new use even if it doesn't raise the property value.
What surprised me in reading this was the definition of "restoration" as an improvement that is added to basis. The example the IRS gives (farm outbuildings) applies to commercial property, but the rules should apply equally to personal property like a home. Then the question would be, was the work needed to be done on the house sufficient to count as restoration, or as repairs. I think if you want to call the work a restoration, you would want the support of a local accountant. My lay opinion is that the work @Candymancan described was not extensive enough to count as restoration (I'm thinking, restoration after a fire or flood), but that can be reviewed by a local expert if they want to claim it.
