Rock salt is mined from Winsford in Cheshire as it is local it offers great value – but can leave a residue on floors inside buildings. This is the same salt that your local council use on the roads and carparks and is a widely used method of de-icing.

Why rock salt?

The main reason rock salt is effective is that it has a lower freezing point than water. By spreading rock salt onto a road, path or driveway, when vehicles or pedestrians use it, the crystals crush and spread across the ice. This will cause a reaction between the water molecules and rock salt, preventing ice from forming.

However, you need to know that rock salt has a limit. On average, rock salt will have minimal effect on temperatures below minus five and have virtually no effect on temperatures below minus ten.

When is the best time to spread salt?

The best time to spread rock salt is before freezing temperatures are forecast. Spreading an even layer of salt on your surfaces prior to reaching freezing temperatures, will help prevent the snow/rain from freezing. Spreading rock salt before the cold temperatures hit will also save on the amount of rock salt needed to make surfaces safe.

How much salt will I need?

The amount of rock salt to be used varies depending on the temperature and location. For example, steep hills and sharp bends will benefit from more rock salt compared to flat and straight roads.

However, we recommend that 10-15 grams of rock salt be spread per square metre. This amount can increase to 20-40 grams if weather conditions are more severe or if rain has fallen before freezing temperatures are predicted.