Another milestone for the Southsea scheme

Southsea’s new sea defences will closely resemble the historic Long Curtain Moat area, thanks to meticulous sourcing of stone that matches the original seawalls.

Approval from Historic England for the materials to be used represents another major milestone for the Portsmouth City Council-led Southsea Coastal Scheme.

Granite will be used for the apron (sloped revetment wall) and Purbeck Limestone will be used for the wall cladding west of Spur Redoubt.

One of the challenges faced by the team was to match the new stones to the original seawall quarry source.

Southsea Coastal Scheme Project Director Guy Mason said: “To ensure the best possible match, we tested samples of the original wall to identify the minerals it was made up of – a process known as petrographic testing.”

“We then investigated quarries to see which stone would be satisfactory to Historic England, being mindful that the stone also had to meet the technical specification of the design to last 100 years,” added Mason.

The approval comes after more than a year of consultation and testing of materials to ensure the new design was sympathetic to the historic area.