Removing Snow From a Roof With Chloride Rock Crystals

Remove ice and snow from a roof to prevent ice dams.

Chloride rock crystals, or deicing salts, work best for removing impacted snow or ice. The salts melt the snow or ice so it flows into the gutters and off your roof. Keeping the roof clear of snow is important to preventing ice buildup that can back up melting snow and cause it to leak into the roof and ceilings. But when using deicers, understand the different types, how they work and which ones are gentler for use on a roof.

Types

There are four primary types of chloride deicing crystals: calcium chloride, potassium chloride, sodium chloride and magnesium chloride. Sodium chloride, or rock salt, melts snow when the air temperature is between 16 and 20 degrees F. It's corrosive to metal and its run-off can pollute streams and other waterways. Potassium chloride is not as harmful to the environment and is less corrosive, but only melts snow when the temperature is above 15 degrees F. Both calcium and magnesium chloride melt snow when the temperature drops well below zero, but calcium chloride is corrosive, toxic to plants and can pollute waterways. Magnesium chloride, on the other hand, is environmentally friendly and not corrosive.

Preparing

Before applying any chloride rock crystal to a roof, remove all of the ice and snow you can. Climb on a ladder to reach the roof and sweep off any snow or loose ice pieces. A roof rake, especially one with an extending handle, is very effective.

Applying

Because most of the chloride rock crystal products are corrosive, do not apply them directly to the roof. Instead, place the crystals into a sock or one leg of a pair of pantyhose. Tie the top of the sock or hose shut and place it directly on top of an ice block or impacted areas of snow. Wait for about a day for all of the snow and ice to melt and sweep or rake off any remaining pieces.

Warnings

Because most chloride deicers are corrosive, handle them carefully. Wear gloves when carrying or opening the bag. Use a scooper to remove the deicer from the bag and to apply it. Keep these products away from pets and children and contact your physician or a veterinarian immediately if they ingest any of the crystals.

References

• Ask the Builder: Deicing Salt and Concrete
• State Farm Insurance: Ice Dams and Attic Condensation
• Canada Mortgage and Housing Corporation: Removing Ice on Roofs