Since its stained glass west window was installed more than 150 years ago, decades of weather damage has left it in need of restoration work that is expected to cost around £1m.
To develop a detailed plan of action for the repairs, York Glaziers’ Trust is working with the minster’s three-man maintenance team and building surveyor Simon Delaney.
Using a magnifying camera, the trust is studying miniature cracks in the stained glass without the need to erect scaffolding.
A sample panel of the glass has been restored so far, while ‘data loggers’ are being used to record moisture, humidity and temperature readings on both sides of the window panes. This data is fed directly back to the Trust at its base in Deangate, York.
The findings will help to determine the specification and timescales for the repairs.
The project is the latest step in a long-running restoration programme at the minster.
Installed between 1859 and 1865, the west window includes a depiction of people and scenes related to the early history of Christianity in Northumbria.
The stained glass was created by Hardman and Co of Birmingham, one of the most esteemed and prolific stained glass firms of the Victorian period.
Mr Delaney, surveyor for Beverley Minster Old Fund, said: “Continuing with the hard work and dedication of people throughout the generations before us, it has fallen on this generation to undertake some large scale projects to protect the Minster.
“Over the last two years we have made excellent progress with the restoration programme including replacement of pinnacles on the roof, installation of a new fire alarm system and significant patch repairs to the roof.
“Now we are putting together a plan to repair the large West window which is in much need of attention.”
The York Glaziers Trust is the oldest and largest specialist stained glass conservation studio in Britain. A charitable organisation, it is dedicated to the care and conservation of historic stained glass across the UK, including at York Minster.