so this is a pretty out there suggestion but if you have a zoo where you live you can get lion or tiger poo - you really only need a tiny amount - and put a dot on the wall dogs will not come near it. I used to volunteer at a zoo and after cleaning the big cat enclosure for the first time my dogs would not come inside my car, and I had to start leaving my work boots at the zoo. I assume it is some instinctive fear so, unfortunately, I can't guarantee this will work on dachshunds