It’s winter, stains are showing up on your ceiling, water is dripping in around the bathroom fans and  pooling in the light fixtures. What’s the problem? “Attic Rain”  Yes, it’s raining in your attic. Moisture from the warm living area has migrated into the attic and condensed on the cold roof deck as frost. This happens  during a cold spell and as the weather warms up, the frost melts raining down onto the insulation and seeps through breaches in the vapour barrier. The result is unsightly water damaged drywall and worse, it can lead to mold. What’s the cause? The most likely causes are poor draftproofing and ventilation. If the vapour barrier around the bathroom fans, lights, smoke alarms etc. is not sealed properly, moisture from the living area will find its way into the attic. Also, new building codes  as of (2010) restrict the amount of soffit ventilation between houses. These unvented soffits are good  for fire safety, but can contribute to the problem by restricting attic ventilation. What can you do? Experts say, operating your central ventilation system during the winter months daily will help expel excess moisture from the house,  that would  otherwise migrate  into the attic. (this is controlled by a wall switch typically located in the hallway by the thermostat). Ensure attic insulation depth  is consistent, level, adequate and the hatch…