One of the most common questions we receive at Icethaw is how much rock salt should I use to effectively de-ice my area?
This a very good question and the answer depends on the temperature as the further the mercury drops, the more rock salt is required to keep your pathways clear of ice and snow.
Normally we recommend 10-15 grams per square metre if it is only ice you are trying to combat. If snow is likely to fall, we recommend upping that to 20-30 grams per square metre to ensure that the ground is still safe to walk and drive upon.
Over time the salt you apply to the ground will become diluted and so it is important to keep re-applying more rock salt over time. This is why you will often see road gritters from your local council gritting the roads throughout the evening and early morning in your local area.
As we all remember from school, ice forms when water reaches 0°C (32F) however when we apply salt to the road, it lowers the freezing point of water which makes it more difficult for the roads and pathways to freeze. Applying rock salt will usually reduce the freezing point of water to approximately -9°C depending on how much is applied through a process called freezing point depression.
Fun fact: Freezing point depression has a wide variety of every uses – e.g. combining salt and ice will make the ice much colder, so much that you can even use it to make ice cream!
If you are interested in preparing for the winter ahead and want to stock up on your rock salt supply, why not view our products – we offer both traditional brown rock salt as well as a cleaner white rock salt in a wide variety of pre-packed sizes or even loose.
References:
https://www.thoughtco.com/understanding-freezing-point-depression-609182
