Worked until it stopped working.
I cleaned concrete porch thoroughly with power sprayer and sprayed cat mace generously, I sprayed area of concern daily after that point.  Using 3/4 of bottle in one week. Worked for one week, now the sweet but very incontinent cat is back, I guess he just figured he can live with the cat mace even though I continue to clean and spray daily.
Rating: 2 stars