Your pole barn roof "rains" in fall because the steel cools off fast at night, often below the dew point of the air inside the building. When warm, humid air touches that cold steel, moisture condenses on the underside of the panels and drips onto whatever is below. The most reliable fix is to keep inside air from reaching the cold steel, and closed-cell spray foam applied directly to the panels does that while also insulating the building. If you've walked into your machine