London To Lewes Way (Roman Road) - Design and Construction

Design and Construction

Five main alignments were used for the road, with local diversions from them to ease gradients and avoid wet ground. Flint and gravel were used over the North Downs and towards the South Downs, with slag from the Wealden iron industry used extensively for the middle sections, sometimes mixed with sandstone from Ashdown Forest and sometimes as a solid mass. At Holtye near East Grinstead a length of road excavated in 1939 revealed iron slag metalling showing cart ruts. Part of this has been left exposed and fenced off by the Sussex Archaeological Trust for viewing.

The width of the road varies greatly between places, from as narrow as 4.4 metres (14 ft) to as wide as 10.5 metres (34 ft) at Butcher's Cross, Hartfield. As no kerb was used the intended width is not known and spreading of material may have increased the eventual width. Where the road crosses hillsides on terraceways the width is about 3.8 metres (12 ft). Where outer ditches are visible on Ashdown Forest they are 19 metres (62 ft) apart.

Thickness of metalling also varies greatly, as does the size of agger. In some places a thick mass of iron slag was laid on the land surface, as at the excavated section at Holtye where the slag metalling was 30 centimetres (12 in) in the centre reducing to 7.5 centimetres (3.0 in) at the edges, laid directly on the clay subsoil and rusted into a concrete-like mass. Elsewhere an earth agger was protected by a much thinner stone layer, as on Ashdown Forest near Five Hundred Acre Wood where only about 7.5 centimetres (3.0 in) of compacted sandstone lumps were bedded on 5 centimetres (2.0 in) of yellow clay. The London end of the road was built of gravel or small flints over a layer of larger flints or pebbles, about 30 centimetres (12 in) thick at the centre, sometimes on a bed of sand.