King’s College is a formerly independent university founded in 1495 in Old Aberdeen. King’s College Chapel is a Category A Listed building and is one of the oldest surviving buildings in the city, with an inscription dated 1504. The chapel is a stout, buttressed, aisled building with detailed window tracery and topped with an imposing Imperial Crown, representing the imperial status of the King James III of Scotland.
Scope of Work
Pictured: Before works: deterioration in protective hood moulding to clock face.
LTM were contracted by Aberdeen University to conserve and repair this historic building. The project encapsulated the Chapel and Library and was implemented over a 5-year programme. Works included: stone replacement, decorative stone carving, lime mortar repointing and lime mortar surface repairs to deteriorating masonry. The works to the Crown focused on selective mortar repairs and replacement ashlar stone to front elevation, parapets, pinnacles, string courses and abutments, culminating in the repair and restoration of the Imperial Crown itself.
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Challenges and Considerations
Pictured: Section of replaced tracery in early 16th Century windows.
The primary challenge was the intricate nature of the stonework and the scale of the building. LTM masons assessed the condition of the stonework and produced a schedule of repair to inform the conservation and repair works. The repair fell into three broad categories:
1) Structural repairs
2) Water damage repairs
3) Aesthetic repairs
An array of replacement stonework was involved, ranging from masonry blocks through to decorative finials and quatrefoil panels. LTM masons cut, dressed and fixed all stonework using traditional methods and materials.
The climax of the project was the repair and reinstatement of the Imperial Crown using stainless steel dog cramps and dowels. Molten lead was poured into the vertical joints to form dog cramps, locking the masonry together - this is a traditional method for tying stonework into place.
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Solutions to Problems
Pictured: Detail of replaced tracery.
The key to sensitive repair and conservation is minimal intervention and use of compatible materials in order to preserve the original fabric. In the first instance, LTM masons replaced only those stones which could not be repaired, using traditional methods and materials throughout - including the use of compatible sandstone, molten lead and gauged hot lime mixes. In other situations it was more appropriate to repair the existing stonework, building up the surface with traditional lime mortars and stainless steel armatures. Alternatively, where contour scaling or delamination was not causing structural problems, LTM masons decided to use other techniques such as micro pinning and mortar flaunching, thereby retaining as much original fabric as possible.
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