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A Disc with rivet at Ampthill Reservoir

On man-made structures, such as church roofs, it was sometimes inappropriate to install a rivet into the existing fabric of the building. In such cases, an asphalt disc was poured onto the surface and the rivet installed in that [1].

There are 129 Discs listed in the TP:UK database. One such example is on the turret roof of St Ninian's Church on the Isle of Man.


  1. The History of the Retriangulation of Great Britain 1935-1962, Fig 7.8, p.225