For home and business owners in the Denver, CO area, ice dams are a familiar sight because of our snowy, cold winters. Ice dams are those masses of ice that you see gathering along the edge of your roofline where it overhangs from the edge of your building.
Ice dams can quickly cause roof damage—severe ones can weigh hundreds of pounds and compromise the structure of your roof eaves. Even more dangerous, ice dams can cause the melted water to get underneath your shingles and ruin your ceilings, wall surfaces, and more.
What Causes Ice Dams?
Ice dams begin to form when the snow melts on warmer parts of the roof and then flows down to the cooler areas where it refreezes. The ice accumulates in these areas and forms a blockage, preventing the rest of the snowmelt from flowing off of the roof. Next, the ice begins to get underneath the roof shingles, melts again, and begins soaking into the sheathing and leaking into the attic. Then, it starts soaking the insulation, basically rendering it ineffective and allowing the leak to go through the ceiling drywall and into your living space. In addition to this, large ice dams can be extremely heavy, causing damage to gutters and becoming a safety hazard for people walking below them.
Ice dams only form when the space underneath the roof deck and inside the attic is above freezing temperature. That causes the warm air underneath the roof to heat the shingles and melt the snow, allowing the water to flow down the roofline to refreeze on the overhanging eave structure. Ice dams typically start or worsen during periods of heavy snow because the snow has insulating properties, trapping the warm air beneath itself.
Why does one house have large ice dams while neighboring properties have none? The answer usually lies in the attic—keep reading to learn how you can prevent ice dams and roof ice damage on your property.
How to Prevent Ice Dams and Roof Ice Damage in Denver, CO
Preventing ice dams comes down to thermal physics—if the air in your attic stays cold, it won’t melt the snow on top of your roof, eliminating the water that ice dams need to form. There are various ways to help prevent ice dams and roof ice damage in the Denver, CO area, including:
Preventing Ice Dams Through Ventilation
Buildings with proper attic ventilation typically don’t have to worry about ice dams, and the reason is simple—by circulating cool air inside the attic space, the roof surfaces don’t hit freezing temperatures and cannot melt snow on the roof. Although it seems counterintuitive, a cold attic fights against ice dams, and a warm attic is at a much higher risk.
There are a few ways to better ventilate your attic to prevent ice dams and roof ice damage:
- In the insulated space between the rafters, you can create an airflow from the soffit to the roof’s peak with a soffit-and-ridge ventilation system. Once installed, the baffles hold back the insulation by one to two inches to create a channel for air to flow past the insulation. The insulation baffles paired with a ridge vent allow air to flow up, creating a continuous path to the outdoor air.
- If you don’t want to install a soffit-and-ridge vent system, you can still use either gable or soffit vents for air intake and use a conventional roof vent to exhaust the air. Typically, an attic vent system should provide one sq. foot of ventilation per 150 sq. feet of the attic’s floor space. That one sq. foot should be the total area of a vent’s openings minus the screening or any other obstructions.
Adequate ventilation of your attic or the rafter spaces helps keep the roof deck cold enough that the snow lying on top won’t melt, which prevents ice dams from forming.
Preventing Ice Dams With Insulation
After installing ventilation in the attic, the next best method to prevent ice dams is insulating the ceilings below the attic. This will help prevent heat from rising up to the deck of the roof and heat it enough to melt the snow on top.
Sealing the air channels from the rest of the building is just as important as the insulation. Gaps around chimneys and plumbing pipes can be a massive source of heat flow into the attic. Sealing these gaps as part of your insulation installation is an excellent idea.
Plus, there’s an additional benefit of comprehensive insulation: reduced energy costs. But, remember, insulation alone won’t prevent ice dams—it needs to be installed in conjunction with improving your attic ventilation.
Preventing Ice Dams by Eliminating Heat Sources
Another reason you might get ice dams in the winter is due to heat sources in your attic that you’re unaware of—usually recessed lighting. Recessed lights can radiate an enormous amount of heat into the attic, heating up the air enough to melt snow and cause ice dams, especially when there isn’t enough ventilation. Replacing old light fixtures with more modern ones that can be insulated can help reduce the heat radiation in your attic.
Other sources of heat include clothes dryer vents, uninsulated HVAC ducts, and improperly vented kitchen or bathroom exhaust fans. You can wrap any of these heat sources with fiberglass insulation to reduce the amount of heat transferred to the attic.
Tips for Reducing Roof Ice Damage
We’ll leave you with some final tips for how to prevent ice dams and roof ice damage:
- Keep your gutters clean—Get rid of any leaves or other debris before the snow comes and ensure that your downspouts are working properly.
- Use a roof rake—Ice dams form quickly after a heavy snowfall, but you can use a long-handled rake to remove the snow from the roof’s edge, which will help prevent them from forming.
- Use calcium chloride—You can also apply ice-melt products or calcium chloride to an ice dam that’s beginning to form to help dissolve it quickly.
- Hire a professional—With how quickly ice dams can form in the Denver, CO climate, sometimes it’s too much to handle alone. Roofing consultants and contractors can help get your roof ready for the winter, safely remove ice dams, and assist with insurance claims should your property get damaged from roof ice damage.
Need assistance with preventative roof maintenance, removing ice dams, or getting your insurance claim? Get in touch with the Advanced Consulting team today!