The tips of the nails are supposed to penetrate through the wood on your roof.
Frozen condensation in attic.
The same thing may be happening on the inside of your attic.
If there is a condensate trap insulate it or just remove it since it probably just runs outside from an attic space.
A point often overlooked is that since it s winter the water freezes on the cold nails.
This is why you see the frost.
Sagging ridgeline drooping ceilings water leaks on interior walls and ceilings jammed doors cracked interior walls near the center of your home creaking sounds.
Signs of condensation in the attic may include the following.
A tool like this shoots nails through shingles.
The air in the attic has water in it and it condenses on the cold metal.
Recognize the signs of stress when too much snow and ice has accumulated on your roof or when you have too much condensation in your attic.
The warm moist air trapped inside of your home is coming into contact with the cold wooden surfaces in your attic forming large damaging water droplets.
Moisture forming on the glass window panes or other flat surfaces.
Condensation forms on the outside of the glass where the cold glass is coming into contact with the warm humid air.