The blizzard we had on December 20th, 2006 was probably the worst I’ve seen since living in Colorado Springs. The 10 minute average wind speed hovered around 45 mph for 3 hours and wind gusts frequently exceeded 55 mph. It was one nasty storm that caused a lot of problems all throughout the country.
For us however, and most people I spoke with around town, the blizzard was troublesome for another less obvious reason. Due to the direction of the wind and the orientation of our home, the wind blew snow into the attic through the louvers of the gable vents. Unbeknownst to me, several inches of snow accumulated on top of the insulation. It wasn’t until 3 days later when the sun came out, heated the attic, and melted the snow, that I had a problem. A big one.
A first, my wife thought the pipe to the toilet in the bathroom had a leak, but there was a splatter pattern to the water. Just as I was crawling around looking for the leak, water started dripping on my back. I looked up and saw the water was coming from the ceiling right next to the bathroom vent. When I went up into the attic to take a look, I discovered the problem.
There was about 3 inches of snow resting atop the insulation extending 4 feet away from the vent. And it was melting … fast. Most of the insulation in that area was sopping wet and had absorbed the water like a sponge. I knew I had to remove the wet insulation, otherwise, come summer time I was going to have one heck of a biological science experiment in my attic.
So, I drive down to Home Depot and purchased two large bags of R-38 fiberglass insulation with vapor barrier. When I returned home, I removed the wet blown-in insulation (yuck) and left the attic bare for about 36 hours. I ran a temporary fan through the attic opening to help evaporate and remove the remaining moisture. The day after the attic was dry, I laid down the new insulation. I also decided to build some covers for the gable vents so I could prevent the wind from blowing snow into the attic in the future.
Both my neighbors used furnace filters and placed them on the inside of their gable vents. This acts as a semi-barrier that allows air through, but stops the snow. Problem is, this storm was so powerful both my neighbors discovered their filters were blown/torn off and they too suffered snow in their attics. So I decided to build some covers I could close for the winter months, then opened in the spring. I used some flat pine board (1″ thick) from Home Depot, stainless steal hinges, and a latch. I treated the wood with a sealant to protect it from moisture.
Now I can close off the gable vents and not worry about snow accumulating in the attic. My solution got its first test about a month later when the next winter storm came barreling in. When I went up to take a look, no snow made it into the attic.
UPDATE: I got tired of climbing into the attic twice a year, so I permanently blocked off the gable vents. To make-up for the lost ventilation, I installed 6 mushroom vents in the peak of the roof.