Newhailes, Musselburgh
Conservation and Restoration of Historic Crown Sheet Glass
The National Trust for Scotland’s philosophy for repairing the window glass was to conserve as much as possible of the existing material. Much of the window glass at Newhailes was original crown sheet, which is no longer produced in large enough panes for most window openings; it is particularly important, therefore, to retain original crown glass wherever possible.
One of the rooms at Newhailes was glazed not with crown glass, but with polished plate glass. Plate glass was made by polishing down rough cast slabs of glass to a fine finish. The thickness of the glass, and the many impurities present in older glass, give polished plate glass a slight but noticeable colour tint relative to today’s pure white glasses.
Where glass panes were intact and all pieces were mechanically held within the framework, the pieces were edge bonded in situ using an epoxy resin with a good refractive index match to the glass, leaving the repaired cracks barely visible. Where panes were too badly broken and had to be replaced, our Barley Bent BB2 glass was used; cylinder glass of matching tint and texture, kiln distorted to mimic the curvature of the original crown.
The colour tint of polished plate glass makes it very difficult to reproduce exactly with modern materials, and in this case, recycled polished plate glass from other buildings was selected to match the appearance of the original glass at Newhailes.
Throughout this project, Barley Studio were able to use their knowledge and experience, both of historic glazing and of conservation philosophy and practice, in order to conserve as much original material as possible and to make sympathetic replica replacements where necessary – following the NTS’s conservation policy to do ‘as little as possible, but as much as is necessary’.