Dunnottar Castle is one of the most dramatic historic sites in Scotland. It was originally an ancient Pictish fortress (5000 BC to 700 AD): "dun" is Pictish for hill fort or place of strength. The site is also believed to be an early Christian site founded by St Ninian in the 5th century. The present castle complex dates from the late 13th century and comprises a number of listed buildings. However the castle never recovered from Oliver Cromwell’s eight month siege in 1651 and is now protected as a Scheduled Ancient Monument.
Scope of Work
Pictured: Works: rough racking to wall head.
LTM were contracted by Dunecht Estate to conserve and repair the historic fabric. Works included: stabilisation, consolidation and repointing work to masonry wall.
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Challenges and Considerations
Pictured: Site access: helicopter delivery.
The castle is situated on a precipitous rocky headland on the North East coast. The site is only accessible by foot and fully exposed to the elements. All materials, tools and equipment had to be air lifted into the castle grounds by helicopter in 900kg loads. LTM masons were particularly concerned about protecting the lime mortar works - the exposure to the natural elements, combined with the saturated ruinous masonry meant that the new traditional lime mortars had to be cured to perfection over a long period. The team rigged up a stable protection system to shield their work from the wind and rain, as well as the occasional vicious seagull!
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Solutions to Problems
Pictured: Dunnottar Castle: scaffolding detail.
The primary task was to consolidate and preserve the historic masonry. The stonework was eroded, largely due to extensive biological growth and recessed cement pointing. The masonry background had to be sensitively prepared to provide a satisfactory substrate, removing all cement and biological growth that would have come into contact with the new mortars.
The precariously dislodged stonework on the slender chimney stacks had to be recorded, gently taken down and rebuilt securely to their original location using stainless steel restraints. This included the careful removal of all vegetation and rough racking the wall core. This repair method encourages maximum water runoff from the walls, preventing the moisture entering the wall fabric and washing out the mortars over time. The finish employs traditional materials and preserves the building without altering its character or appearance.
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