St. Helen’s Chapel, Durham Cathedral - East Window

In 2024, we were contracted to carry out conservation on a quarry panel containing a medieval roundel in the East Window of St Helen’s Chapel, Durham. We proposed that the medieval glass be cleaned, conserved, framed and returned to the building with localised environmental protection (EPG) to prevent further deterioration.

The medieval roundel was set into quarry glazing, so was removed from the surrounding glass in order to be protected. As the lead was extremely fragile, both the quarry glazing and the roundel were dismantled. The medieval glass was carefully cleaned, edge-bonded and repaired, with an exterior plate applied to support the bonded areas. The roundel was then re-leaded and placed into a bespoke manganese bronze frame.

The quarry glass was also re-leaded, incorporating a piece of True Vue Conservation UV Glass into the space once previously occupied by the roundel.

The quarry panel and the framed roundel were then reinstalled into the window, with the roundel set to the inside and affixed to new support bars. The fixing system allows air to flow between the roundel and the panel, preventing the formation of damaging cycles of condensation.