How does gritting roads work?

Road Salt & Grit Facts & Myths

Monday 9 January, 2023

As the largest and one of the longest established winter gritting contractors in the South East, we understand the gritting process and use the best gritting and snow removal machinery to always offer you the best winter gritting service. 

How does gritting work?

We use white marine salt and this article explains how gritting works and how our winter gritting contractors keeps your business open and safe.

Part of our role as a commercial gritting contractor is educating our clients on how, why, and when we grit. Like the winter weather, gritting and snow clearance isn’t always predictable. The success of our gritting teams depends on several factors and is always weather dependent: 

  • Ideally, we salt roads when the weather is dry as winter grit can be washed away because of rain. However, if rain falls this can sometimes freeze and cause ice before we have treated your paths or access roads.
  • If temperatures fall below minus 8 degrees centigrade gritting salt will not melt ice and is less effective overall at temperatures below minus 5 degrees centigrade.
  • We review the Met Office weather reports regularly but sometimes it is hard to predict exactly where, when and how much snow will fall. 
  • There is no best time to grit your company premises, as a rule, our winter gritting teams go out in the evening, but we continuously monitor the Met Office weather forecast for more information.
  • If the weather is cold and we are out gritting, frost and ice can set in before we complete our gritting round, in this situation, we may have to revisit your business.
  • Similarly, if we grit and then snow falls again during the night, we might have to return to remove the fresh snow.

Common facts and myths about gritting

What is rock salt?

Rock salt is over 90% pure sodium chloride (salt), the remaining insolubles consist of Keuper Marl that protects the quality of the salt. Rock salt can be stored for many years if it is kept dry. Rock salt is generally used by UK Highways Authorities to grit public roads and motorways. The grit is effective but it is dirty and leaves roads and cars covered with a brown residue. 

What is white marine salt?

White de-icing salt is almost 100% pure sodium chloride. It is a marine salt harvested from sustainable sources. Clearway Gritting use a marine salt supplied that harvests salt from sources around the Mediterranean Sea.

We use marine salt due to its purity, it does not leave behind the same messy brown residue as traditional brown rock salt (grit). This makes it perfect for commercial uses on car parks, pathways, pavements and playgrounds where cleanliness is important.

With a purity level of almost 100% sodium chloride, every particle plays a part in the de-icing process.

Conforms to BS3247:2011, the British Standard for de-icing salt.

How does salt prevent frost and ice forming?

Salt spread on your business premises, for example your company car park, mixes with any moisture to create a saline solution. This saline solution freezes at lower temperatures than water,so frost and ice doesn't form on the road, even though the temperature is below freezing for water.

At temperatures below minus 5 degrees centigrade, the effectiveness of the salt is reduced.

Does salt melt snow?

No! If salt is spread across a fresh snowfall, it has not had the chance mix with the snow to form the saline solution which lowers the freezing point.

Salt only effectively melts snow when it is less than 40mm deep and constant traffic movement can move the salt around.

Does grit work when snowfall is heavy?

If snowfall is heavy and continues to fall the salt may not be able to mix with the snow adequately and snow will settle. 

However, if we return to remove the snow this is much easier to do if salt has already been spread.

It’s too cold for snow

This is true but does not often affect the UK. There is a link between the air temperature and how much water can be held, but this is only likely to happen when the temperature is below -40 degrees Celsius. At this temperature the air doesn’t normally have enough moisture to create snow.

In Summary

If you need a winter gritting contractor, call our Clearway Gritting team in St Albans on 01727 851837. We have teams working in Huntingdon, Aylesbury, Harlow, High Wycombe, and Milton Keynes. These local gritting teams serve a variety of retail parks, industrial parks, supermarkets, universities, schools and smaller private businesses in Hertfordshire, Cambridgeshire, Essex, Buckinghamshire, and North London. 

Gritting Services

Cost effective and carefully planned preventative and reactive road and pavement gritting for the effective prevention of ice and the clearance of snow.

Gritting Services

Car Park Gritting

Preventative and reactive car park gritting services to the private and public sectors in Hertfordshire, Bedfordshire, Buckinghamshire, London and the South East. Our car park gritting vehicles are always prepared and ready to provide service at very short notice, often within 1 hour of an initial request.

Car Park Gritting

Gritting Quote

Contact our services team for a competitive Winter & Snow Clearance contract quote.