A £2million appeal is being launched to save Lichfield Cathedral’s Chapter House.
The building is suffering from water damage and stone erosion and the roof is also in need of urgent repair.
As a result there is now a “substantial risk” to the interior and the collection housed within it.
The library has been housed in the upper room of the Chapter House since 1758 and is home to items such as 15th Century hand-copied manuscripts of Chaucer’s Canterbury Tales, one of the three surviving original copies of Christopher Saxton’s maps of Tudor England, and a manuscript of illustrations issued by and signed by Charles I.
The Very Revd Adrian Dorber, Dean of Lichfield, said: “Our Cathedral is beautiful but fragile.
“It falls to us to look after it and keep it in good repair for the rest of this century.”
The appeal will be launched in February and comes almost 12 months after £3.7million was raised to restore and reinstate the Herkenrode stained glass windows.
The Dean added: “We hope we can raise funds from a wide variety of sources and get the job done in 2016/2017.
“We want to show Lichfield Cathedral and its proud city to many more people, so playing our part in strengthening the economy of the area and ministering to a wider and more diverse public.”
The Chapter House is the only two-storey one in the UK. It is currently home to a long-term exhibition that focuses on the Anglo-Saxon history of the site. It includes the St Chad Gospels, the Lichfield Angel and associated Christian items from the Staffordshire Hoard.