I have a well-built 4-yr old 50 X 30 ft. bungalow with a well-pitched roof, fully-vented soffits, foot-square gable vents and three evenly-spaced ridge vents on east slope. Round patches of frost tend to form on top of the thick blown insulation in the attic cavity, right under the ridge vents, usually after a late spring snowstorm/windstorm, even when there is no snow at all on the roof. As the attic warms up, the ice melts and the water finds pinholes in the poly barrier.(The water is better at finding pinholes than I am!)Is an attic fan the solution? Perhaps installing absorbent baffles under each vent to dissipate the moisture?
Answer:
What you describe, I believe, are not ridge vents. A ridge vent is attached to the very ridge of the roof and if it has baffles, there is no way anything can blow in there. The situation you describe is most common with mushroom vents and in thoses cases, it is a matter of the domes on them being a bit too high so the wind can swirl in under them.
