One of the most common complaints about skylights is that they tend to leak. While this complaint is warranted, skylights very seldom actually leak. The water that is dripping down skylight opening and causing all of the mess is actually condensation. This condensation tends to form when the cold from the attic and roof surface collides with the warm air from the interior of the house on the glass.

The amount of condensation depends on the difference in temperature when the warm and cold air mixes. The best way to cure this issue is using closed cell polyurethane foam insulation from the attic to insulate the skylight well and prevent the massive heat loss that is occurring.