Rising dramatically from sea cliffs on the edge of the Firth of Forth, Tantallon Castle has weathered the storm of enemy invasions, fiery sieges and even played a role helping to train Dambusters in defeating the Nazis.

But having maintained an impressive presence on the outskirts of North Berwick in East Lothian since the 14th century, more recently its chief foes have been old age and weather.

One of 70 Historic Environment Scotland properties closed since summer 2021 amid concerns over the state of their masonry, assessing its stonework and making problem areas safe posed problems which its centuries-old adversaries would be familiar with – how to penetrate its towering defences and narrow wooden bridge to get things done.

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The challenge – eventually solved at Tantallon by drafting in a helicopter to deliver scaffolding from above – has been one of many faced by the heritage organisation, as it tries to tackle what it’s called “the biggest conservation challenge facing Scotland’s historic buildings.”

Tasked with carrying out high-level masonry checks on a massive and complex scale at centuries-old structures across the land, the body has encountered everything from frozen iPad screens which have hindered work in the depths of winter, to the intimidating challenge of individually inspecting thousands of stones, one by one.

On the way, there have been invasive weeds to be plucked from cracks in medieval masonry and the relentless task every homeowner will be familiar with – checking thousands of the roof slates are all secure and in place.

The Herald: Dryburgh Abbey inspection workDryburgh Abbey inspection work (Image: Historic Environment Scotland)

According to Craig Mearns, HES Director of Operations, the controversial decision to seal off dozens of properties to the public for months to allow inspections to take place – in some cases, attracting criticism that precious little work seemed to be getting done at certain sites – has proved vital to enabling complex work to begin safely.

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While it has also enabled masonry inspectors to carry out tactile, up-close checks which revealed previously unnoticed problems that would not have been identified from ground level or visual checks alone.

Writing in his HES blog, he said: “Our physical tactile inspections have been uncovering problems that would not have come to light using traditional methods of visual inspections.

“I’m absolutely certain that restricting access until we can check all of these sites has been the right thing to do; it is our legal duty.

“We understand that this was a decision which brought concern, frustration and disappointment to many,” he added.

Full and partial access has now been restored at around 30 sites, including Dundonald Castle in South Ayrshire, which once housed descendants of Robert the Bruce, 500-year-old Burleigh Castle in Milnathorpe, spectacular St Andrews Castle and Incholm Abbey.

“Surveying these sites is no easy task – especially as our meticulous approach involves checking all of the stonework by hand,” added Mr Mearns.

“On average, it takes around a month for a team of inspectors to check each site. This ranges between four person days for smaller sites, to 136 person days for larger, more complex sites.

“At Dumbarton Castle we inspected over a kilometre of masonry walls, constructed of thousands of individual stones.”

The Herald: Linlithgow Palace stonework is carried outLinlithgow Palace stonework is carried out (Image: Historic Environment Scotland)

Dumbarton Castle, where William Wallace was taken following his capture in 1305, is set to reopen this spring. Elsewhere, Holyrood Abbey in Edinburgh opened earlier this month, while access is expected to be restored to the majority of Aberdour Castle and Lochleven Castle later this month.

Masonry inspections on buildings from Orkney to Dumfries and Galloway are being carried out by a conservation team of 20, supported by numerous others from HES working on other elements of the project.

“However, with around 40 sites still left to be checked they can’t be everywhere at once,” added Mr Mearns.

He said hands-on checks have revealed defects which have been fixed ‘on the go’, including repairs to slates and lightning conductors, removal of invasive weeds, re-bedding of high-level stones and the removal of dangerous materials.

“Where more involved work is needed, we’ve put in place interim solutions which restore as much access as possible to our properties,” he added. “We’ll return to carry out further repairs once we’ve got solutions in place.”

Carrying out checks during winter has created particular issues, he said.

“At times the screens of the iPads that we use for recording survey results stopped working because it was too cold. There were other times when it was so cold that potential loose material was frozen onto the monument.”

HES decided to close 20 of its sites in summer 2021, followed by a further 50 in January last year.

The move, which saw historic sites sealed off with unsightly metal barriers and tourists greeted by locked doors - was necessary after initial inspections at sample sites revealed concerning issues with high level masonry.

The organisation has cited the impact of climate change, age, the roofless nature of so many structures and well-intentioned but poor repairs of the past as contributing to concerns over high level stonework.

It says it is amongst the first heritage organisations to adopt the pro-active approach and is sharing both the methodology and findings with peer organisations.  

Mr Mearns said a decision had been made to prioritise sites where it was difficult to fully restrict access due to roads or neighbouring properties being checked first.

That, however, led to some smaller, less well-known sites taking priority ahead of more popular HES properties, sparking criticism that some sites highly popular with tourists, including Tantallon Castle - used as a training location for Second World War Normandy invasion and RAF bomber crews including the famous Dambusters  - were closed for months with apparently little work done.

“We do appreciate that it might have appeared that sites had been restricted and no work was taking place, but I’d like to reassure people that was not the case,” he added.

“Work has been ongoing. This has included pre-inspection work, such as checking the suitability of the land around the site to withstand the weight of heavy machinery like specialist access platforms or checking rope access points.”

He added that work is currently underway at Caerlaverock Castle in Dumfries, Dirleton Castle in East Lothian as well as at Tantallon.

Inspections are also set to begin at sites in Orkney. Spanning 5,000 years of history and posing particular problems due to their archaeological significance, they include Midhowe Chambered Cairn, St Magnus Church and Noltland Castle. 

Preparation tasks including ground archaeology work and ecology reports have to be conducted prior to masonry inspections being carried out.

Mr Mearns added: “It is really important that we do our best to preserve them for future generations and this programme of work is crucial to achieving that.

“We regret any short-term inconvenience the inspection programme may cause, however, this will be overshadowed by the longer-term benefits.”