Rock salt, commonly used to melt ice and snow on driveways and walkways, might seem like an effective solution for de-icing roofs. However, using rock salt on roof shingles can lead to significant and costly damage. Here are the primary dangers of using rock salt on roof shingles and why alternative methods should be considered.
1. Corrosion and Deterioration of Shingles
Chemical Damage
Rock salt contains sodium chloride, which is highly corrosive. When applied to roof shingles, the salt can accelerate the deterioration of the roofing material. Asphalt shingles, the most common type of residential roofing, are particularly vulnerable. The salt can break down the adhesive properties and the protective granules on the shingles, leading to premature aging and the need for costly replacements.
2. Damage to Metal Components
Corrosive Effects
Roof structures often include metal components such as flashing, gutters, and nails. Rock salt can cause these metals to corrode over time. The corrosive action of sodium chloride can weaken these components, leading to leaks and structural damage. This is especially problematic for the longevity and integrity of the roof, as well as the safety of the home.
3. Environmental Impact
Harm to Surrounding Vegetation
When rock salt is washed off the roof by rain or melting snow, it can seep into the soil around your home. This runoff can harm vegetation, affecting grass, shrubs, and trees. Sodium chloride disrupts the soil’s nutrient balance, making it difficult for plants to absorb water and essential nutrients, potentially leading to dead or unhealthy vegetation around your property.
4. Health Risks
Potential Hazards
Handling rock salt poses health risks. Inhalation of rock salt dust can irritate the respiratory tract, and direct skin contact can cause irritation or burns. Additionally, if ingested accidentally by pets or children, rock salt can be toxic. Ensuring safety while applying and cleaning up rock salt is challenging and risky.
5. Ineffectiveness in Extreme Cold
Limited Melting Capabilities
Rock salt is effective only at temperatures above 20°F (-6°C). In colder climates, it becomes less effective, necessitating the use of more salt to achieve the desired melting effect. This increases the amount of salt applied to the roof, exacerbating the damage to shingles and metal components.
6. Water Damage
Ice Dams and Melting Issues
Improper use of rock salt can lead to uneven melting of snow and ice, causing ice dams to form. Ice dams occur when melted water refreezes at the roof’s edge, preventing proper drainage. This can cause water to back up under the shingles, leading to leaks, water damage, and mold growth inside the home.
Alternatives to Rock Salt
Safer Solutions
1. Calcium Chloride: A safer de-icing agent for roofs, calcium chloride is less corrosive and works at lower temperatures compared to rock salt.
2. Roof Rakes: Using a roof rake to remove snow manually helps prevent ice buildup without using chemicals.
3. Heated Cables: Installing heated cables along the edge of the roof can effectively prevent ice dams by ensuring consistent melting and proper drainage.
4. Professional Roof Maintenance: Regular inspections and maintenance by roofing professionals can identify and address potential issues before they become severe.
Conclusion
While rock salt might be an effective de-icing solution for driveways and walkways, its use on roof shingles poses significant dangers. The corrosive nature of sodium chloride can damage roofing materials and metal components, harm the environment, and pose health risks. Homeowners should consider safer alternatives and engage in regular roof maintenance to ensure the longevity and safety of their roofs during the winter months.
