Environmental Protective Glazing f0r Endangered Stained Glass Windows
“The installation of a protective glazing system is a crucial part of the preventive conservation of architectural stained glass”
Corpus Vitrearum Guidelines for the Conservation and Restoration of Stained Glass, 2nd ed, 2004
Why Environmental Protection?
Our fragile heritage of stained glass is endangered through its exposure to atmospheric moisture in the form of rain and condensation. The presence of moisture encourages loss of painted detail, corrosion of medieval glass and biological growth such as moulds and algae, which hold moisture longer on the surface of the glass thus accelerating the rate of deterioration.
In transmitted light – damage to painted detail
How does it work?
Internally ventilated environmental protective glazing (EPG) allows air from within a building to pass freely over both sides of the stained glass. The air, being of equal temperature on both sides, keeps the glass dry and in as near museum conditions as can be achieved within the architectural setting.
What are the benefits?
Relieved from their practical function of being a climatic barrier, the protected stained glass windows are displayed as works of art in EPG that significantly retards further deterioration.
Conservation treatments can be minimised, for example re-leading can often be avoided and the existing leadwork conserved.
Non-invasive treatments, such as cold painting to replace lost or faded painted detail, can be introduced to enhance the visual appearance.
Where can examples of our EPG systems be seen?
Keith Barley pioneered the use of EPG systems in the UK over 40 years ago, designing and installing site-specific systems to protect some of our country’s most prized historic glass. Keith’s passion for preserving our fragile heritage has resulted in these systems being adopted by leading cathedral glass conservation studios such as Canterbury, York and Lincoln as well as many independent studios throughout the country.
Environmental Protective Glazing systems installed by Barley Studio can be found in York Minster, Southwell Minster and Howden Minster; Lichfield Cathedral, Ely Cathedral and Durham Cathedral; stately homes such as Longleat House and Blickling Hall; and parish churches such as St Nicholas’, Stanford on Avon, Northamptonshire and St Mary’s, Fairford, Gloucestershire, that house some of the finest collections of medieval windows in the world. Internationally, Keith Barley has designed systems for The Museum of Fine Art, Boston and St Patrick’s Cathedral and The Metropolitan Museum, New York.
The Lady Chapel of Lichfield Cathedral, with Barley Studio’s Environmental Protective Glazing and Wire Guards
protecting the world-famous Herkenrode windows