Winter gritting salt and why it’s so effective

Every year the UK spreads millions of tonnes of winter gritting salt on our roads, pavements and car parks to battle the icy conditions of a UK winter. But why do we use winter gritting salt?

Winter surfaces covered by ice can cause many problems, from a simple slip to a major incident. To ensure people are kept safe and sites remain operational, surfaces need to be de-iced, and this is usually done by distributing winter gritting salt onto the surface.

How does winter gritting salt work?

Water freezes at zero degrees Celsius, but the freezing point of water changes when you add other substances. Add salt to water and the chemical nature of the water changes – it becomes a salt solution.

A salt solution freezes at a lower temperature than water, up to about five degrees lower. This means that as you put salt on to your roads, paths and car parks, it then mixes with the water already on the ground (from dew, rain, and water in the air as it condenses), which forms the salt solution.

Salt solutions freeze at a lower temperature – about minus seven degrees, rather than zero degrees were it just pure water.

This explains why it is much more effective to put winter gritting salt down in advance of a big freeze, rather than putting it onto ice once it is already there.

Does winter gritting always work?

At OUTCO we mainly use white marine salt as our de-icing agent. Salt is generally 100% effective down to a temperature of -9 degrees Celsius, which is extremely cold and seldom experienced in the UK.

Does winter gritting salt work when it snows?

Salt only effectively melts snow when it is less than 40mm deep and even then, there is a risk that the snow dilutes the salt to the point that it becomes ineffective. This is why snow clearance is usually carried out after snow has fallen, followed by a winter gritting visit to prevent the further formation of ice.

Keep your customers safe and book your winter services

Our advice couldn’t be simpler: don’t wait until it gets cold before booking your winter services.

To find out how we can work together, or to obtain a free winter gritting quote or site inspection, please contact us today.