Humidity in my house right now 13%, which is normal during winter. I have cathedral ceilings with no attic. It is an older, very large, 100% wood house, log cabin style. I ran 1 gallon humidifier for a week and now have water dripping exactly above the humidifier. It drips like one drop every 10 min at night and more often during day time. It is 21F outside. The roofer had said the roof is fine. Is it because of the humidifier? But the house is huge and I would think the moisture would spread around the house, not accumulate somewhere. The distance between the floor and the ceiling is also substantial. What is happening, please help.
I bet your ceiling is cold.
Consider my cold drink on a hot day. Humidity has spread around the clubhouse. The outside of my glass is dripping wet and I must use a coaster. Why does the humidity stop just on my glass and not breeze on by? It is because my glass is cold, and passing humidity that bumps into it condenses into water.
So too your roof. You have a cold spot for whatever reason. Ambient humidity in the house stops there and condenses. You could try to address the spot, or give up on humidifying the great room and concentrate on humidifying bedrooms.