The Grand Coulee Ice Dam

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March 1, 2015 by Jean

When my retiree group met for lunch last month, the topic of removing snow from roofs came up. I scoffed at the current fad for roof-raking, arguing that Maine building codes require roofs that can handle a heavy snow load and that I didn’t remember people removing snow from the roofs in the heavy winters of my childhood. One friend responded that she had always raked the snow from her roof and would continue to do so.

As the snow continued to pile up with no melting in between, and as stories of roof collapses and advice to clear roofs of snow were featured on the news, I began to worry that I had gotten it wrong. While there was no more snow on my roof than in previous years, I also realized that this year was different because my new addition has changed the configuration of my roof and because heat from constant use of my woodstove was melting snow around the chimney that then turned to ice as it ran down the roof and refroze. I did a lot of online reading about design snow loads and the weight of a cubic foot of snow, and I was reassured that the snow we were getting was all light, fluffy stuff.

My research also taught me that the biggest problems were not caused by the weight of snow on the roof, but by ice dams, ridges of ice that form at the edge of the roof and back up melting snow into pools of water that can leak into the house. That curtain of big icicles forming where my new and old roofs come together probably indicated an ice dam. But this was located where the power lines come into the house; even if I had a roof rake, I knew better than to mess around with it near the power lines.

But when I was out shoveling our most recent snowfall off the back deck about a week ago, I looked up and noticed a big ridge of ice along the roofline above the deck. There were no icicles here; just a wall of ice. And it was big, running almost the entire length of the house and about 10-12” high at its biggest point. This wasn’t just a few inches of ice at the edge of the roof; this was the mother of all ice dams, the Grand Coulee ice dam! And it was only February, with lots of cold and snow still to come.

My anxiety about the ice dam urged me to take action. Everything I had read, especially about ice dams, was that it was foolish to try to deal with them by yourself. Forget about DIY and call in a professional. I looked up roofers in the yellow pages, paying particular attention to those that advertised ice and snow removal. By the time I went to bed on Sunday night, I had chosen three possible roofing professionals and listed them in order of priority.

On Monday morning, I sat down at my desk to call them in that order. I was concerned about costs and also about how soon they would be able to do the work. (I imagined the possibility of a 2-3 week delay.) When I called the first company, I got an office manager who immediately dispatched a foreman to come look at my job and give me an estimate. If I accepted the estimate, she explained, they would do the work immediately.

Forty-five minutes later, the foreman was ringing my doorbell, and we went out to walk around the house and look at the problem area. Getting the entire roof cleared of snow and ice was prohibitively expensive (more than $800), and he suggested just clearing the part of the roof with the big ice dam. In the end, I decided on a compromise: clear the north-facing roof of snow and address the ice dam, and do the same for the small roof over my new front porch.

Three hours after I called the roofing company, the work was completed and the Grand Coulee ice dam was no more. And I was feeling very pleased with myself. My self-satisfaction was short-lived, however. As day turned to evening and temperatures plummeted on what promised to be the coldest night of the season, my house started to make ominous noises – pops and thuds and loud bangs! I worried that I had made a mistake by only clearing part of the roof and had a vague memory of reading that uneven snow loads increase structural stress on the roof. I had also read that if your roof starts making popping sounds, you should evacuate the house and call the fire department to come inspect your roof. The rational part of my brain noted that there were no signs of impending roof failure in my house – no cracks in the walls or sticking doors – and that the loudest sounds seemed to be coming from the part of the roof that had been cleared, not the part with heavy snow on it. But my anxiety rose and rose. I did eventually get to sleep, but it wasn’t exactly a restful night.

By morning, I had decided to contact my town’s building inspector and the contractor who built my addition for advice. Both reassured me that the sounds I had heard were most likely caused by the wood framing contracting in the extreme cold. But they also thought it would be a good idea to clear the snow from the rest of the roof. My contractor offered to send out one of the guys who works for him to do the job, at a much lower cost than I had been quoted by the roofing company. Justin arrived at my house in late morning and spent more than four hours shoveling snow from the roof – including some 4’ deep snow drifts.

As our cold weather continues (February set a new record for cold), the frame of my house continues to pop and thud at night. But I no longer worry that my roof is about to cave in. Next year, I will buy myself a roof rake, I will remove snow to prevent ice dams, and I won’t scoff at friends who keep their roofs clear of snow.