The first two days of this week we were caught at the edge of the major winter storm that covered most of the eastern United States. In addition to freezing rain and snow, we had bitterly cold temperatures, perhaps as low as -10º. On Tuesday morning Sibylle discovered frost on the ceilings in both front bedrooms. We immediately contacted our builder as the house has a warranty.
His theory is that the insulation in the attic isn’t properly distributed and that the small areas of frost that we saw are a result of very cold air on one side of the drywall, and considerably warmer and moister air on the other side. He doesn’t think that there is any leak or that snow was blown into the attic space through the soffit vents. His insulation crew was going to stop at the house on Friday to correct things but their previous job took longer than expected. Our builder tells us that they’ll be back in this area next week and will visit then.
His explanation makes sense and is backed up by the pattern of frost we saw. It was primarily in the corners of the room, where it might be harder to insure blown-in insulation was properly deep. The forecast for this week includes more bitter cold air and the potential for more snow. Hopefully this time we won’t have enough temperature difference to generate frost inside the house.