Dungeness Sound Mirrors, Kent
More from: How to repair concrete
The three sound mirrors, or ‘listening ears’, on the beach at Dungeness, Kent, were built in the 1920s and ’30s to detect enemy aircraft approaching across the channel, before radar rendered them obsolete. Their proximity to the sea has accelerated the rate of decay and there is widespread corrosion of reinforcement and delamination of the concrete.
English Heritage has commissioned a series of investigative repairs on the mirrors – which are now scheduled as monuments (legal protection specifically for archaeological sites) – that will explore treatments that might be transferable elsewhere. The richly patinated surface of the mirrors is a complex amalgam of weathered aggregate and many varieties of lichen. Chris Wood from English Heritage’s building conservation team is also experimenting with yoghurt to encourage lichen reinstatement. The works were carried out by Rowan Technologies.