Snow was heavy in Minnesota last week. Today, we will talk about what causes ice dams, and how to prevent and fix them. 

Tessa explains what an ice dam is and how they are formed. She shares that most houses can fix this through proper air sealing and insulating of the attic space. Reuben adds that most people think this can be improved by adding ventilation to the roof but this is different. 

They talk about various roof designs and valleys that are prone to ice dams, as well as locations of air penetrations in the roof, bath fans, and how they contribute to the dam formation. Moreover, they discuss air flow and leakage, attic bypasses, and the importance of adequate attic ventilation. Reuben enumerates the types of vents and other heat sources. Tessa highlights that fixing air bypasses can be a very difficult and messy job.