I, too, have had mirrors desilver because of moisture. They sit several inches
above the backsplash and I am sure, water has never actually splashed to them -
nor has it fallen behind backsplash. It's just moisture condensed on the
All of my bathrooms have backsplashes with caulk sealing them. None of them
touch the mirrors. Not just in this house, but in the previous house as well.