I have my garage at below grade level due to a drive that goes around to the rear of my house. The entire rear wall is below grade and the one side wall slopes back so a good portion of that is below grade. The other side wall is block, but is a wall between the garage and basement. The humidity in the room is terrible, I have rusty tools, smelly car interiors, etc. I had a heating/AC square duct exposed that dripped in the summer. I insulated around that and stopped that issue. Is there anything else to be done? I have the higher end garage doors with insulation too. Short of leaving the doors opened all the time, is there anything I can do. I dehumidifier would be essentially dehumidifiying the entire earth because the garage door is not a perfect seal. I was thinking about screwing XPS to the walls and leave that exposed. I am OK with pink walls, but will this help? I have not water leaks, so I guess it is coming from the cool block below grade issue.