Ice dams are a common problem for homeowners in cold climates. They form when snow on the roof melts from heat inside the attic and runs down to the eaves where it refreezes. This ice buildup prevents water from draining off the roof and can lead to serious water damage, mold, and roof rot. The best way to prevent ice dams is to improve attic insulation and ventilation to reduce heat loss and meltwater. But even well-insulated attics can develop ice dams during extreme winters. So what else can you put on your roof to prevent ice dams? There are several solutions ranging from simple to more complex and expensive.
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Remove Snow Regularly
The simplest solution is to regularly remove snow from your roof, especially overhangs and valleys where ice dams tend to form. Use a roof rake to remove snow safely from the ground before it melts and refreezes. Be sure to wear slip-resistant shoes and avoid overreaching to prevent falls. Remove snow after any significant accumulation, and keep pathways clear on the roof to allow meltwater to drain. Regular snow removal may not prevent all ice dams, but it will reduce the amount of snowmelt available to contribute to them.
Install Heating Cables
Heating cables, also called heat tape or heat trace cables, produce a low level of heat to melt channels in ice dams and snow on roofs. The cables are affixed directly to the roof along the eaves, valleys, and trouble spots prone to ice buildup. They are powered by electricity and turn on automatically when they detect snow or ice. Heating cables range in price from $1-$4 per linear foot. Installation is simple enough for DIYers, but requires electrical work to wire an outlet accessible from the roof. Heating cables provide targeted melting where ice dams form, though they use electricity and must be manually turned off at the end of winter.
Apply Deicing Compounds
Deicing compounds, also called ice melt, can be applied to specific areas on the roof to melt channels for drainage. These compounds contain sodium, magnesium, calcium, or potassium chloride which lower the freezing point of water to melt through ice. They come in solid granule or liquid forms. Apply a channel of ice melt along roof edges and seams where ice dams originate. Reapply after precipitation or high winds. Deicing compounds are highly effective and affordable at $1-$3 per pound, but must be reapplied regularly. Take care using deicers on metal or tile roofs as some compounds can degrade or discolor these materials.
Install Roof Flashing
Roof flashing is a sheet metal component designed to seal joints and direct water off roofs. Installing metal drip edge flashing along eaves improves drainage and reduces seepage of meltwater into the attic. Step flashing applied up roof-wall joints also seals this leak-prone area. Carefully installing new flashing requires roofing skills. Flashing provides passive prevention at vulnerable spots and lasts for years. But it can be costly, ranging from $3-$8 per linear foot of drip edge, and does not guarantee complete ice dam prevention.
Apply Liquid Membranes
Liquid roof coatings and membranes provide a seamless, waterproof barrier along the roof edge. These can be applied from a can or rolled on to seal vulnerable spots. Liquid membranes contain asphalt, rubber polymers, or acrylic resins. They fill cracks and adhere tightly to the roof surface when dry. Prices range from $50-$100 per gallon. Applying a uniform coating takes skill. But high-quality membranes last 5-10 years and offer reliable ice dam prevention. Small leak repairs can also be made as needed.
Attach Heated Roof Panels
Heated roof panel systems consist of modular panels with embedded heating cables that affix to the roof deck. The systems include all wiring and controls needed to operate automatically based on conditions. Panels provide targeted heat where and when it’s needed along eaves and valleys. Professional installation is required and costs around $85-$100 per square foot of heated panel. This is an expensive option but provides seamless, maintenance-free protection against ice dams over a 15-20 year lifespan.
Improve Attic Air Sealing and Insulation
Preventing heat loss into the attic is the most effective way to avoid ice dams long-term. Improving attic air sealing and adding insulation reduces melting on the roof by keeping interior heat inside the home. Sealing gaps around chimneys, pipes, wiring, and the attic hatch prevents warm air intrusion. Increasing attic insulation to an R-value of R-49 or higher also minimizes heat transfer and condensation. Though air sealing is tedious work and extra insulation has upfront costs, it provides lasting ice dam prevention and utility savings.
Comparing Ice Dam Prevention Options
To decide which solution is best for your roof, compare the pros and cons of each option:
| Method | Pros | Cons |
|---|---|---|
| Remove Snow | – Inexpensive – Accessible for DIY |
– Labor intensive – Not fully effective |
| Heating Cables | – Targeted melting – Automatic operation |
– Electricity required – Manual shutoff needed |
| Deicing Compounds | – Highly effective – Inexpensive |
– Reapplication required – Can damage some roofs |
| Roof Flashing | – Long-lasting – No maintenance needed |
– High upfront cost – Professional installation required |
| Liquid Membranes | – Seamless coverage – Long-lasting when applied properly |
– Skill needed to apply – High cost for full roof |
| Heated Roof Panels | – Fully automated – Maintenance-free |
– Very expensive – Professional installation required |
| Attic Air Sealing & Insulation | – Addresses root cause – Provides utility savings |
– Significant upfront work and cost – Ongoing maintenance needed |
As shown, each solution has advantages and disadvantages that may make it more or less suitable depending on your roof type, problem areas, and budget. Generally, a combination of methods is needed for the best control.
Recommended Solutions by Roof Type
The optimal ice dam prevention plan depends on your specific roof design and materials. Here are the best solutions for common roof types:
Asphalt Shingle Roofs
For asphalt shingle roofs, focus on:
– Regular snow removal
– Heating cables affixed at problem areas
– Liquid membrane coatings for durable protection
– Improved attic insulation to at least R-49
Shingles are vulnerable to damage from heavy snow and ice. Heating cables provide safe melting without shoveling while liquid membrane seals leaks at seams. Better insulation also reduces attic heat loss to minimize melting.
Slate or Tile Roofs
Effective ice dam prevention for slate or tile roofs includes:
– Deicing compounds or heated panels for spot melting
– Adding roof drip edge and step flashing
– Improving attic insulation and ventilation
Avoid shoveling slates or tiles which crack easily. Deicing compounds or heated panels give targeted melting. Flashing helps guide runoff while insulation reduces attic heat loss.
Metal Roofs
For metal roofs, key ice dam prevention strategies are:
– Snow removal using roof rakes
– Deicing compounds compatible with metals
– Applying liquid-applied membrane at seams
– Adding roof insulation as needed
Metal roofs shed snow well, so raking before melt helps. Deicers must be metal-compatible. Liquid membrane seals seams and insulation further reduces snowmelt potential.
Low-Slope Membrane Roofs
On flat or low-slope roofs, focus on:
– Deicing compounds over large areas
– Liquid-applied membrane reinforcement
– Heated roof panels at trouble spots
– Improving insulation if an insulated roof
Flat roofs require wide deicing application and additional membrane coatings. Heated panels provide targeted melting as needed. Insulation helps if already part of the roof assembly.
Conclusion
Ice dams pose a threat to roofs and attics in cold climates, but can be prevented with the right solutions. For most homes, a combination of snow removal, deicing compounds or heating cables, and improved attic insulation provides effective protection. Liquid membranes and flashing offer more permanent solutions. Heated roof panels give automated prevention, but at a high cost. Consider your roof type, problem areas, and budget when choosing the best ice dam prevention plan. A proactive approach saves roofs from damage and prevents costly leaks into attics and interiors. With the right preparation, homeowners can keep ice dams from forming and maintain a dry, damage-free roof through winter.