What you should know about using de-icing salt
When winter rolls around, de-icing salts are one of the most common solutions to keeping the roads safe and driveways clear. Literal truckloads of rock salt are ferried about and spread on both private and public property to prevent car accidents, slips and all manner of other kinds of injuries.
De-icing salts include magnesium chloride, calcium chloride, sodium chloride and potassium chloride. But are these products safe? And what are their implications for surface protection?
How do de-icing salts work?
The basic principle underlying chemical de-icing is the fact that solutions containing salt tend to freeze at lower than 32 degrees Fahrenheit, the temperature that water freezes at. Placing a de-icing solution onto a surface melts the ice, creating a new solution that has a freezing point lower than water.
This keeps surfaces free of ice, making just about any structure more safe for those using it. As mentioned, they're often used on roads to prevent car accidents, but can also be applied to steps, driveways, door jambs and other areas.
However, they can also have negative consequences.
What are the effects of using de-icing salts?
One of the biggest impacts from using such chemicals is that their runoff has a variety of negative effects on the natural environment. It can build up to near-toxic levels, and can also contaminate groundwater, soil and vegetation.
Moreover, de-icing salts can also have damaging effects on stone surfaces. The brine solution that results from applying these chemicals can have incredibly destructive effects on brick, masonry, concrete and natural stone in general.
If the brine penetrates a porous surface and is absorbed, it will leave behind solid salt compounds in the surface once the water eventually evaporates. At best, this will cause unsightly salt staining. At worst, when this salt crystallizes, it will expand and break apart the material. You can start to see your brick or sandstone practically melting away thanks to these products.
What is the solution?
The solutions, pardon the pun, can come in many forms. First of all, whether you're worried about snow and ice damaging your stone in general or the de-icing brine penetrating it, you'll definitely want to have your surface sealed with Dry-Treat's META CRÈME™ or, for brick, DRY-TREAT 40SK™.
Secondly, you'll want to limit the use of de-icing salts. If you can avoid them entirely, all the better, but if you must use them, do so sparingly. Choose wisely where you apply them, and certainly avoid doing so close to brick structures.
You can do this by leaving a 12-inch buffer zone on areas adjacent to vulnerable surfaces, as well as by rolling up your sleeves and getting rid of snow and ice the old-fashioned way – with a shovel.