Calcium Chloride On Roof And How To Get Rid Of It

Calcium Chloride On Roof And How To Get Rid Of It


February 18, 2022

If your roof is experiencing ice dams, you might reach for calcium chloride to melt the ice and snow.

This is a good move as ice dams can be damaging. They form icicles that hang off the roof and drag down the gutters and cause water to accumulate and leak in your house.

What is calcium chloride?

This is an inorganic compound that classifies as a salt. Since it’s a desiccant, it can be used as a drying agent. Calcium chloride is usually sold as “ice melt.”

This is why it’s marketed for use as an effective ice and snow removal product. But, is it safe to use on your roof? Here’s what you need to know about calcium chloride before you buy it. 

The Dangers Of Calcium Chloride 

Calcium Chloride On Roof And How To Get Rid Of It

If you’ve heard that calcium chloride can cause damage to your roof, this is not a myth.

  • Calcium chloride corrodes roofing nails, which can lead to loose shingles.
  • It can also corrode your gutters, aluminum, and fasteners, which is especially risky for metal roofs as it can speed up their corrosion.
  • When used on roofing shingles, calcium chloride can effectively remove ice dams but it can also stain them.
  • After using calcium chloride on your roof, you might notice a white residue that’s left behind. This can be corrosive, so make sure you wash it off your roof with water. A power washer can be used to do this effectively and quickly, but make sure you use it on a low pressure setting if your roof is made of metal or your shingles are old or otherwise damaged.

How To Use Calcium Chloride For Ice Dams

Calcium Chloride On Roof And How To Get Rid Of It

If you need to eliminate ice dams from your roof, you might have heard this common tip: fill the leg of pantyhose with calcium chloride and then place it on the roof so that it lies across the ice dam. It can also overhang the gutter.

Why this works is that the calcium chloride will melt the snow, producing a channel so that the water can flow to the gutters. It’s more effective than sprinkling the substance over the roof.

However, make sure you fill the pantyhose legs without them being overstuffed. Tie off the ends. If you have a long ice dam you want to dissolve, you should place pantyhose filled with calcium chloride every four feet, at a perpendicular angle to the gutters.

While calcium chloride is usually recommended for removing snow from driveways and roofs, you have to be careful with plants and grass around your house. Be sure to protect them if you think that they’ll come into contact with the product because they can die from exposure to it. 

How To Prevent Ice Dams In Future 

Calcium Chloride On Roof And How To Get Rid Of It

There are some important steps you can take to maintain the good condition of your roof and prevent ice dams from forming in future.

  1. Clear your gutters and downspouts. This will prevent ice dams from forming because clear gutters will ensure better water circulation. This will prevent blockages and also prevents the accumulated water from freezing inside the gutter.
  2. Clean your roof. By investing in a roof rake, you can clear away snow before it accumulates and causes problems. Make sure it’s long-handled and has wheels so that it won’t damage the roof shingles. This is a safe way you can clean your roof from the ground, keeping it in good condition. 
  3. Add attic insulation. You should insulate your attic as this will prevent heat from moving through the roof, which can cause water to freeze and then thaw, causing you problems. An eight-inch layer of insulation will achieve this while also ensuring you can maintain heat inside the home.

Calcium Chloride Vs Rock Salt: Which One Should You Use? 

Calcium Chloride On Roof And How To Get Rid Of It

If you’re not sure if you should use rock salt or calcium chloride on your roof to remove ice dams, let’s examine what rock salt is. This is basically sodium chloride.

When it gets mixed with water, rock salt has a freezing point of 14 degrees Fahrenheit, which is lower than water without salt. This is why roads can be sprayed with a salt solution before it snows to protect them, but it can also be used after snow removal to prevent ice forming in future. 

While rock salt is cheap, it can’t work when temperatures are lower than 14 degrees. Rock salt is extremely corrosive – it can degrade concrete and wood, so it’s not ideal for removing snow from your roof. 

By comparison, calcium chloride can work at temperatures as low as -62 degrees Fahrenheit. Although it is more expensive than rock salt, it is safer.

For example, when used on concrete it melts ice at a lower temperature and a faster rate than other ingredients. Since it breaks the bond between the ice and surface of concrete, it produces less corrosion than what you’ll experience with other, more harmful, substances such as rock salt.  

How To Use An Ice Melt Product On Your Roof 

Calcium Chloride On Roof And How To Get Rid Of It

You might be wondering how an ice melt product actually works.

Since water freezes at temperatures of around -32 degrees Fahrenheit, when salt is added to it the water will have a lower freezing point so it won’t turn into ice at its usual freezing point. The salt therefore helps to prevent the water molecules from joining as ice. 

If you don’t want to use calcium chloride in pantyhose to remove snow from your roof, you can find products on the market that contain this ingredient. However, there are some important things to bear in mind when using an ice melt on your roof. 

  • If the ice melt is in the form of tablets, throw them onto the roof before it snows. Then, after it has started snowing you can throw a few more. When the snow falls, it will melt into water and fall off your roof.
  • If you have small granules of calcium chloride, we’ve already told you that you need to stick them into pantyhose before putting them on the roof. But it’s a good tip to put one pantyhose in your gutter or next to the gutter, because it’s where ice dams usually form.
  • Be safe by throwing the calcium chloride product onto the roof from the ground. This is better than getting up onto a ladder, especially if the outdoor conditions are wet or it has already started snowing.
  • If you can see salt on the ground from the calcium chloride that has been melted on the roof, you should shovel or sweep it away as soon as possible. And, as mentioned earlier, make sure you’ve protected your plants so that they won’t die from the salt exposure.
  • When choosing products containing calcium chloride, always check that they don’t contain any rock salt in their ingredients. 

At what temperature does ice melt? 

When temperatures are above 32 degrees Fahrenheit, ice begins to melt and it becomes a liquid. That said, you don’t need the air temperature to be higher than that for snow to melt, especially if the sun is shining.

What should you look for when buying an ice melt?

Make sure that the ice melt can work on your roof material. A pro tip is to test the product on a small area of the roof, in an area where it’s not easily noticeable, before using it on the entire roof. 

Can you chip ice off your roof?

Chipping ice off your roof is risky because you could damage the roof. You’ll also have to climb the roof to be able to chip the ice away, which can put you at greater risk of injuries. 


If you want to eliminate ice and snow from your roof, you might have heard that salt can work well. While you should avoid rock salt, what about calcium chloride? 

We’ve given you all the information you need to know about using calcium chloride on your roof, how to apply it safely, and how to prevent ice dams from forming in future.

While ice dams can damage your roofing structure, they don’t have to be given free reign anymore – now you know how to send them packing!

Reference Articles:


James Weldon is a professional roofing contractor with many years of experience on the job. He does not only handle large projects and provide excellent services for his company’s many clients; James Weldon also dedicates his spare time to teaching others useful tricks of the trade. Using BuildCampus as an avenue to reach many roofers and aspiring roofing contractors, James Weldon continues to provide high-quality educational posts and buying recommendations for anyone who visits the website.