When faced with icy buildup on their roofs, many homeowners ponder the use of rock salt, a popular de-icer for driveways and sidewalks.
But can the same remedy be applied to your home without repercussions?
If you’re looking for answers about using rock salt to deice your roof during the cold winter, this article is for you.
Let’s break down the dos and don’ts of rock salt usage and ensure you make an informed decision to maintain your property properly.
What is an Ice Dam?
An ice dam is a buildup of ice that forms at the roof edge and valleys, preventing melted snow and frozen water, from draining off the roof.
As the water pools behind the dam, it refreezes, causing the ice dam to grow larger over time with each cycle of freezing and thawing. If not addressed, ice dams can cause significant damage to the property.
How do Ice Dams Form?
Ice dams form when warm air from the attic leaks through the roof above the eave line, causing snow to melt. As the melted snow flows towards the gutter, it encounters colder temperatures and refreezes, creating the ice dam.
The cycle continues as the snow melts, and the warmer water runs over the dam and refreezes, forming icicles and making the ice formation and dam thicker. This process exacerbates the issue and can lead to more significant property damage if not addressed.
Can I Use Rock Salt on My Roof?
While rock salt can melt snow and ice on roofs, it’s not recommended due to its corrosive nature. Continual application can corrode vulnerable parts like nail heads, seals, and flashing. Best suited for hard surfaces like concrete, routine use on roofs can harm shingles, nails, and other fixtures. Use sparingly and with caution.
Rock salt, while it might not immediately harm shingles, poses risks to the structural elements of a roof. It can corrode the nails securing your shingles, leading to potential damage.
Beyond the roof, the salt will eventually melt and flow, threatening to corrode downspouts, driveways, sidewalks, and even masonry. Brick or stone structures can particularly suffer from salt-induced freeze-thaw damage, similar to what we see on concrete driveways.
Why you should not Use Rock Salt on your Roof
Ineffective and Impractical:
Rock salt’s limited effectiveness to cure ice dams in temperatures above 20°F makes it impractical for regions with colder climates, where ice dams are more common.
Additionally, the sheer volume of snow and ice that accumulates on a roof during winter would require an impractical amount of rock salt to melt significant ice dams, rendering it an inefficient solution.
Corrosion of Nails and Building Materials:
The corrosive nature of rock salt can lead to the deterioration of nails holding roof shingles together in place. As the nails corrode, they can cause unsightly stains and streaks on the roof surface.
Moreover, weakened nails can result in loose or damaged shingles, putting the roof at risk of leaks and further structural damage.
Damage to Other Building Components:
Rock salt runoff can have detrimental effects on many other building materials and components, such as downspouts, driveways, and sidewalks.
The corrosive properties of salt can eat away at these materials over time, potentially leading to costly repairs and replacements.
Harmful to Garden Plants:
When rock salt mixed with water drips off the roof and reaches garden beds, it can poison the soil and harm plants.
Many plant varieties are sensitive to salt exposure, and prolonged contact with salt can cause leaf loss, branch dieback, and even plant death.
Accelerates Masonry Damage:
Salt accumulation on stone or brick masonry can exacerbate freeze-thaw damage. As water with dissolved salt infiltrates porous surfaces, it expands upon freezing, leading to cracks and weakening the masonry’s structural integrity.
Over time, this can cause extensive deterioration and the need for expensive masonry repairs.
Alternative Salts to Removing Ice Dams
If rock salt has left you cold, don’t worry – a whole flurry of other products is ready to break the ice.
Let’s take a frosty journey through some alternatives to melted salt and see if we can find the best ice dam buster for you.
1. Calcium Chloride
Calcium chloride is favored for melting ice on roofs, especially for handling ice dams. Its effectiveness in melting ice rapidly, even at lower temperatures, makes it an attractive option. Like rock salt, it’s less corrosive to metal but can still harm plants and concrete.
Methods like filling old pantyhose with calcium chloride can create channels to break up large ice dam or dams. While effective, it’s generally more expensive than rock salt, and its application must be done carefully.
2. Magnesium Chloride
Magnesium chloride is an eco-friendly alternative to potassium chloride for melting ice, effective above 5 degrees Fahrenheit and less harmful to metal. However, it can damage concrete surfaces and is generally more costly than traditional rock salt.
Its use might be restricted by budget considerations and limited effectiveness in extremely cold climates, where temperatures drop below 5 degrees Fahrenheit. Both magnesium and potassium chlorides are options for ice melting, with temperature limitations for effectiveness.
3. Table Salt
Some individuals opt for table salt as a deicing agent instead of rock salt, as both have the exact same chemical composition.
Table rock salt substitute however is merely finer rock salt crystals and shares its corrosive and staining properties. Breaking the ice with tools can also lead to significant roof damage.
How to Remove Ice Dams without Using Rock Salt
Insulating the Attic Floor:
- Adding more insulation to the attic floor can be done with fiberglass batts, blown-in cellulose, or foam insulation.
- Proper insulation helps maintain a temperature barrier, preventing warm air from escaping into the attic and keeping the roof cold.
- A colder roof reduces the risk of snow melting and refreezing, contributing to ice dam formation.
Ventilation:
- Ridge vents and soffit vents should be installed to ensure proper air circulation in the attic.
- Cold air enters through the soffit vents and exits through the ridge vents, creating a continuous airflow in the attic space.
- Adequate ventilation helps maintain a uniform roof temperature, reducing the conditions that lead to ice dam formation.
Air Sealing:
- Inspect the attic for gaps, cracks, and holes around chimneys, vents, electrical wires, and other openings.
- Seal these gaps using weather-stripping, caulk, or expanding foam to prevent warm air from reaching the roof deck.
- Proper air sealing helps eliminate heat transfer to the roof, minimizing the risk of ice melting and refreezing.
Use a Roof Rake or Broom:
- Use a roof rake with an extended handle to safely remove snow from the roof’s lower edge, preventing snow and ice buildup.
- A roof broom can also gently sweep away accumulated snow to prevent ice dams from forming.
- Regularly clearing snow during winter helps maintain a snow-free roof, reducing the chances of ice dam development.
Consider Professional Roofers:
- For severe ice dams that pose significant risks, hiring professional roofers experienced in ice dam removal is recommended.
- Professional roofers may use steam machines or other specialized techniques to safely melt the ice dam without causing damage.
- Proper ice dam removal by experts can prevent further damage to the roof and gutters.
Safe Use of Deicer:
- Using a deicer, choose calcium chloride instead of rock salt, as it is less damaging to the roof and surrounding materials.
- Apply the deicer in targeted channels across the ice dam to allow safe runoff and prevent damage to plants and building materials.
- Be mindful not to overuse the deicer, as excessive application can still have negative environmental effects.
Weaken the Ice Dam:
- Removing snow just above the ice dam helps prevent further growth and accumulation.
- Once the ice dam weakens, carefully use hand tools, such as a rubber mallet or shovel, to break up and remove the remaining ice.
- Avoid damaging the roof’s surface while removing the ice dam.
Can I Use Rock Salt on My Roof? FAQs
Is it OK to put salt on the roof to melt ice?
Using salt to melt snow and prevent ice buildup is simple, but it’s not advisable for ice removal from your roof. According to a reputable roof repair contractor, salt is not an effective solution for curing ice dams as it can only melt ice at temperatures as low as 20 degrees.
Can you put salt on the asphalt roof?
Typical ice dam doesn’t cause much damage to asphalt shingles, but it can lead to corrosion of the nails holding the shingles to the roof.
Does rock salt damage asphalt?
Rock salt, or sodium chloride, can do more harm to unsealed asphalt as it accelerates the natural freeze/thaw cycle in the winter, leading to increased deterioration and a shortened lifespan of the asphalt.
How do I stop my roof from escaping heat?
To prevent heat loss on roofs, insulating the loft cavity ceiling is the most straightforward method. Properly insulating the loft or ceiling is essential, ensuring no gaps are left, especially around hatches, electrical fixtures, and pipework.
Conclusion
Rock salt has its merits in combating ice on hard surfaces like concrete. Its corrosive properties make it a risky choice for roofs.
Regular application threatens the integrity of vital roof components, from nail heads and seals to shingles and eavestroughs.
Given its corrosive oxidizing agents, rock salt can accelerate wear and tear, leading to potential long-term damage.
Homeowners seeking effective de-icing methods should approach the application of rock salt on roofs cautiously, reserving its application for select situations and always considering alternative, roof-friendly solutions.