12 May 2015

As the weather starts to improve, Northamptonshire County Council will begin its extensive ‘surface dressing’ road repairs across the county.

The work is being carried out to provide a cost-effective way of preserving and extending the life of highways in Northamptonshire.

What is surface dressing?

Surface dressing involves hot tar being sprayed on to the road surface and overlaid by chippings which are rolled on to the surface. When the tar cools it sets and holds the chippings to the surface of the road.

The technique creates what are commonly known as loose chippings and as a result traffic is slowed to 20mph to reduce the danger of partially embedded chippings flicking up in the first few days.

Loose chippings are swept away within 24 hours of the initial dressing, and again within three days.

A heavy roller is used after initial treatment and the surface is usually fully embedded after around a week, due to the action of traffic moving across it.

Cllr Michael Clarke, county council cabinet member for transport, highways and environment, said: “Surface dressing allows us to carry out repairs to large areas of the highway in a very cost-effective way.

“This treatment seals and increases the texture of the surface of the road so that the surface is less susceptible to damage in the future. A good surface dressing treatment can last many years.

“However I would urge motorists to slow down on the newly laid surface to minimise the risk of the loose chippings flicking up and damaging vehicles.”

Driving safely

The carriageway is safe to drive on following application of the chippings, provided speeds remain below 20mph. For safety, people are advised to drive slowly, keeping their distance, and to avoid turning or braking sharply. Motorists should also avoid overtaking.

Surface dressing is dependent on fine weather and, as such, the programme of works is liable to change.

Roads that have been identified as having early deterioration are treated in this way to stop any further, more extensive damage occurring.

Surface dressing as a maintenance process has three major aims:

  • To provide both texture and skid resistance to the road surface.
  • To stop the disintegration and loss of aggregate from the road surface.
  • To seal the surface of the road against ingress of water and thus protect its structure from damage.