Ground-breaking new material used in York Minster conservation

York Minster will be the first building in the UK to use a revolutionary new glass to protect one of its medieval masterpieces – the Great East Window.

The groundbreaking UV resistant glass will be used as part of the external protective glazing for the 15th century window, which was designed by influential medieval artist John Thornton.

The stained glass from the window, which is the size of a tennis court and the largest single expanse of medieval glass in Britain, has currently been removed and is being painstakingly conserved by York Glaziers Trust.

The work to conserve and restore the Great East Window is part of the York Minster Revealed project which is due for completion in 2016.

“We are delighted to be at the forefront of this new cutting-edge technological advance, which represents a wise investment in the long term care of the building,” commented York Minster Revealed Director, Mark Hosea.

Previous protective glazing has acted as a weather shield and kept glass, pigments, lead and conservation materials dry, but has not been an adequate barrier to Ultra Violet radiation. This impacts on any epoxy resin used in the conservation of the stained glass and leads to a yellowing discolouration of that resin after prolonged exposure.

Earlier forms of UV-resistant glass have relied on laminations of glass and a UV-resistant foil, but in the new Restauro UV © glass the UV resistance is an integral part of the glass itself. The product has been developed by Glasshuette Lamberts of Germany, the world-leading producer of mouth blown antique glass.

“It is reassuring to know,” said Sarah Brown, Director of the York Glaziers Trust, “that we are now able to offer total environmental protection for all aspects of the conserved window.”

Visitors to York Minster can learn more about the work to conserve the Great East Window, including seeing up-close completed panels, in the Orb – a contemporary metallic dome located in the cathedral’s East End.