Understanding ice damming
Over the last ten years, a dramatic increase in precipitation and snow build-up on roofs due to climate change has exacerbated the ice damming problem and even led to roof failures. Both new homes and existing buildings can suffer from this condition. Ice damming occurs when snow on your roof melts and refreezes, causing water to back up and potentially damage your home. Even flat roofs can be impacted by ice damming conditions. Insulation, ventilation, and attic bypasses are the root causes of ice damming on a pitched roof. If not addressed promptly, ice dams can lead to costly repairs and long-term degradation of the facade and structure of the building.
Causes of ice damming
Be warned: there are a ton of misunderstandings and bad advice on how to fix ice damming conditions from the building industry. Ice damming on a pitched roof occurs when snow on the roof melts and refreezes near the roof's edge, creating a dam that prevents proper drainage. This can happen due to poor attic insulation, ventilation, and attic bypasses that lead to snow melting and refreezing. Snow load, roof pitch, and roof design can also contribute to how significant ice dams are or how much water collects on the roof. You might have noticed I didn't say insufficient insulation. This is because there has to be balance; too much insulation can lead to hot spots or blocked attic ventilation. Too many attic bypasses or blocked attic ventilation can lead to a warm attic space that leads to a specific type of ice dam. Regardless of the design or type, attic ventilation cannot compensate for significant attic bypasses. I have found that irrespective of how much attic ventilation a roof system has, even mechanical ventilation cannot make up for a substantial attic bypass. Often, mechanical ventilation can make it worse. There are scientific reasons for this that get a little technical for a blog. Still, anecdotally, time and again, I have had customers who have brought their insulation levels up and added passive or mechanical ventilation with no difference or even made the problem worse.
Signs of ice damming on your roof
Ice damming on your roof can lead to costly water damage if not addressed promptly. Look out for these signs to catch it early:
Any number of Icicles hanging from the roof's edge can potentially be considered ice damming
Ice build-up in your gutters
Water seeping into your home through the ceiling
Visible water stains on the ceiling, walls, or exterior siding
Wet insulation in the attic
Impact of ice damming on your home
Ice damming can severely damage your home by causing water to seep into your roof and walls, leading to leaks, potential mold growth, or even structural failure. Additionally, ice dams can add excessive weight to your roof, increasing the risk of structural damage. It's crucial to address ice damming promptly to safeguard your home from these costly and disruptive issues.
Strategies to prevent ice damming
First and foremost, document the condition, especially if any warranty or insurance issues are associated with your situation, and keep track of work or changes you have made to mitigate it. If you can safely get pictures of the roof and the extent of the icicle or damming conditions, this can help document the extent of the conditions and point toward the root causes. To prevent ice damming, ensure your ceiling is airtight and your attic is well-ventilated and insulated to keep the roof cool. Sealing any gaps in the air barrier at the ceiling or leaks, called attic bypasses in the industry, is critical to prevent warm air from escaping into your attic. Attic bypasses are the leading cause of ice damming conditions in an attic space. Cleaning your eave vents and checking the baffles inside the attic are important maintenance items you can do annually to ensure your attic is well-ventilated. Check gutters and flashing materials in the spring and fall to maintain proper drainage along the eaves and valleys. Also, ensure that your roof has adequate ice and water shields to prevent leaks from ice damming. The lower your roof pitch, the higher your ice and water shield should go.
Insulating your attic
Improving your attic insulation is a significant improvement when trying to reduce energy costs and improve comfort. Proper insulation helps maintain a consistent temperature in your attic and minimize overheating during the summer or ghosting and condensation on the ceiling during the winter. While important, adding or replacing the attic insulation is the last step or improvement when it comes to the work in the attic. Trust me on this: the worst thing you can do is add 18" of blown-in insulation and find out the ice damming conditions are worse, and you have to go back up there next summer and remove it all to get to the root issues and eliminate the ice damming conditions. Here are a few steps to improve your attic insulation and improve your homes energy efficiency:
Check the current insulation levels in your attic to ensure they meet the recommended R-value for your region.
Remove these types of insulation: old fiberglass batts that are poorly installed or vermiculite. 5 Things You Need to Know About Vermiculite | Family Handyman
Seal any air leaks in the attic, such as around ducts, chimneys, and light fixtures, to prevent warm air from escaping.
Upgrade bathroom fans and ductwork in the attic, including the kitchen fan or dryer, and then add insulation to the ductwork and plumbing vents for improved performance with these systems.
Properly ventilate your attic to prevent moisture from accumulating and contributing to ice dam formation. Good ventilation can also help regulate the attic temperature.
If your current insulation levels are insufficient, consider adding more. This can help retain heat in your home and prevent ice dams from forming.
Use insulation materials appropriate for your climate and attic space, such as fiberglass and cellulose. I recommend using the same type of blown insulation: If you have fiberglass, use fiberglass, and if you have cellulose, stick to cellulose.
If you're unsure how to improve your attic insulation, do your homework or consult a professional like an energy rater to assess your insulation needs and recommend the best solutions for your home. A great resource is here: Guides A-Z | Building America Solution Center (pnnl.gov)
Proper ventilation techniques
Proper ventilation techniques are essential in maintaining ambient temperatures and dry conditions. Ensure your attic has the recommended insulation to prevent heat from escaping into the roof. Additionally, roof vents should be installed to allow proper air circulation and keep the roof's temperature consistent. GAF has a great calculator here: Attic Ventilation Calculator: Proper Roof Ventilation | GAF Regularly check and maintain your ventilation system to ensure it works effectively to maintain a dry attic space. Often, eave vents and gable vents become blocked by natural lint or even paint after a house is painted. Shingles can also block ridge vents during a reroof. Inspecting your attic at different times of the year can give you insight into the performance of the ventilation and the attic space. Look for moisture, ice, or frost and any mold conditions or dark spotting developing.
Installing heat cables
When preventing ice dams, a last-ditch effort that should only be used after all other attempts have failed to mitigate ice damming conditions fully is installing heat cables or heat trace. Heat cables are expensive to install and operate and must be carefully designed to remove dams and maintain drainage through the gutter system and downspout onto a safe area that will prevent ice in walk areas. Slips, trips, and falls from ice on the ground are some of the most common hazards associated with ice damming, while one of the deadliest aspects is falling ice and snow. Here are a few key points to consider when installing heat cables:
Placement: Heat cables should be installed along the roof’s edge, gutter system, and in areas where ice dams are likely to form. If ice damming is present on an upper roof section, it's also important that a lower roof section also needs heat cables to create a continuous drainage plane all the way to a safe area on the ground or drainage system.
Installation: It is recommended that heat cables be installed by professionals before the winter season starts to ensure they are ready when needed and that a switch is available to turn on and off the system as needed.
Usage: Heat cables should be turned on during snowfall or when ice begins to form to prevent ice dams from becoming a problem.
By installing heat cables properly, you can minimize the impact of ice damming and protect your home from potential damage.
Clearing snow from your roof
Suppose you're in the middle of the winter or near springtime and have ice damming forming in your room. In that case, clearing snow from the entire roof can be essential to prevent snow and ice from accumulating and water seeping into your home and exterior walls. I specifically said the whole roof because removing a heavy load from one side only can cause structural problems with your trusses, and removing only the eaves often has the effect of raising the dam higher up the roof line, which can cause more leaks. Here's how to effectively clear snow from your roof:
Use a roof rake to remove snow from your entire roof.
To prevent damaging your roof, avoid using a shovel, ice chipper, or chainsaw (lol).
Ensure you're tied off properly and know the risk. I like starting near the edge and working inward to know precisely where the roof's edge is. Watch your step!
Clear snow after each snowfall to prevent ice buildup. This can get expensive, but so are water damage and insurance claims.
Consider hiring a professional if you cannot safely clear snow yourself or have never done this work.
By clearing snow from your roof regularly, you can help prevent ice damming and protect your home from water damage.
Professional assistance and maintenance tips
Professional assistance for preventing ice damming can be beneficial if you are unsure how to address the issue effectively. Some benefits of seeking professional help include:
Identification: Professionals with experience testing and identifying problem areas in your attic that are the root causes of ice dams.
Preventive Measures: They can provide recommendations on how to prevent ice dams from forming in the future.
Efficient Solutions: To mitigate ice damming risks, professionals can implement solutions such as proper air sealing, insulation, and ventilation.
In addition to professional assistance, here are some maintenance tips that can help you prevent ice damming on your property:
Clearing Snow: Regularly remove snow from your roof to prevent it from melting and refreezing.
Sealing Leaks: Seal gaps or leaks in your attic to prevent warm air from escaping and causing snow to melt on your roof.
Insulating: Ensure your attic is adequately insulated to maintain a consistent temperature and prevent melting snow.
Ventilating: Properly ventilate your attic to regulate temperature and reduce the likelihood of ice dams forming.
By combining professional assistance with regular maintenance, you can prevent ice damming on your property and protect your home from damage.
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