Encounters with Ice Dams in the Field
While we were getting hit with winter storms a couple weeks ago I blogged about ice dams. As the snow began to pile up on roofs we got calls reporting damage to homes. The cause: ice dams. Today I went out to a home in the Northland that had significant damage to their cathedral ceiling.
This picture shows the water damage to the ceiling. I began to assess what was the cause by running my blower door while doing an infrared scan of the ceiling. The infrared showed some thermal deficiencies, but nothing appeared to be a smoking gun. As I moved through the house I was looking for clues. Usually the insulation grade is pretty consistent throughout a home, so I begin to look at other areas where I can actually see the insulation to get ideas about what may be occurring in areas I cannot see.
Once I got to the utility area I looked to see how the cantilevers (or overhangs) were insulated and a light bulb went off. This is what I saw:
I realized that if they used batts of insulation that were undersized (and therefore ineffective) here, most likely they took the same short cut in the ceiling. The insulation is insufficient and acting more as an air filter for the hot air than a thermal boundary. Once the warm air passes through the batt it is convecting near the roof line. This is warming up the snow and allowing it to melt. The reason we see the most significant damage in the area pictured above is because this is where the melted snow naturally tends to drain from the roof.
We will be working with the homeowner to correct how their cathedral ceiling is currently insulated. Energy efficiency rebates will be utilized to add insulation. Being an energy auditor is a lot like being a detective. I’m happy to report that we have solved the ice dam mystery for this homeowner. Have an energy mystery of your own? Contact us today.