That path would then presumably be used as an escape route for water that may tend to get trapped behind the ice dam.
Rock salt to melt ice on roof.
Calcium chloride is typically regarded as the best performing ice melt for fast melting and long lasting action.
Check the pantyhose periodically as it might shift as the ice melts.
While safely on the ground toss a roofmelt tablet onto the roof.
The tablets help prevent roof damage by melting through ice dams and allowing water to drain safely.
Halite also known as rock salt is strictly the mineral sodium chloride.
Rock salt usually contains grit and other bits of gravel that are meant to help gain traction whether it is on a roadway walkway driveway or stairs.
In our experience magnesium chloride is the safest and all around best easy to find ice melt you can use in an absolute emergency.
It also does not work well below 20 degrees fahrenheit.
Rock salt is one of the most affordable methods for melting ice.
Ice melt typically is a blend of sodium chloride magnesium chloride pellets and calcium chloride pellets.
Each of these ice melt products lowers the melting point of ice to a different temperature point.
In large concentrations these chemicals will also damage nearby shrubs and grass.
That is where the word rock in rock salt comes from.
Rock salt will only melt ice down to 20 f 6 67 c so it will only work at all on warmer below freezing days in the narrow range of 20 to 32 f 6 67 to 0 c.
It should be no surprise then that it is the first thing many people think of to remove ice dams.
Salt socks work on the principle that the ice melting compound is contained in a linear form which when laid across an ice dam will melt a channel through the ice.
A do not put salt on your roof.
However rock salt is a form of sodium chloride which corrodes metal including the metal nails holding your shingles in place.
Ice melt is sometimes presented in the form of flakes such as industrial blue ice melt.
You can read here more about all those types of ice melt.
The pros of rock salt.
It melts to 15 f.
Rock salt can also leave permanent stains on your roof and walls.
Do not spread rock salt or calcium chloride across your entire roof as these chemicals are corrosive and can reduce the life of your roof flashing along with metal gutters and downspouts.
Ice melt is typically a blend of sodium chloride with other minerals such as magnesium and calcium.
Except in times of extreme shortages rock salt is also widely available making it easy for home and business owners alike to locate and purchase the material when they need it.
Sodium chloride or rock salt is highly corrosive.
Rock salt works down to 5 f and helps provide instant traction on snow on ice.