IT was grey and cold in Helensburgh, three mornings ago, when The Herald arrived at Hill House to take photographs. The rain held off for the duration of the shoot, but then, quite typically, a drizzle began to fall.
Rain has been the implacable enemy of Hill House, Charles Rennie Mackintosh’s domestic masterpiece, ever since it was opened in 1904.
The house was commissioned by the Blackie family, who had made their fortune in book publishing. And what a striking house it is. In the words of the glasgowmackintosh website, it combines “traditional Scottish architectural values with modern international aspirations. Delicately stencilled interior decoration using designs of roses, thistles & other plants creates the feel of an indoor garden enhanced by clever use of abundant natural light provided by the open site, overlooking the Firth of Clyde.” The stylish fittings and furniture, it adds, include Mackintosh’s famous ladder-back chairs; and beautiful decorative coloured glass and tiles are used throughout.
But, as splendid as it is (and Brad Pitt, for one, really likes the place), Hill House has been undermined by decades of rain. Each year, on average, rain falls onto the property for 193 days and the house is now showing signs of serious deterioration, traceable to what the National Trust for Scotland, its owners since the early 1980s, refers to as Mackintosh’s experimental design, coupled with his trial of new materials.
All sorts of solutions were considered - including, reportedly, a plan to demolish the house and erect a facsimile in its place. The solution the trust opted for was an ingenious one: a fine perforated mesh ‘box’, made of stainless steel, that covers the house entirely, allowing it to dry out at its own pace while conservation work is carried out inside.
The innovative, semi-transparent chainmail box, which will be in place for between seven and ten years, was designed by the award-winning, London-based architects Carmody Groarke, whose CV includes the V&A Members’ Room in London and a memorial for the victims of the 7/7 bombings in the capital in 2005. “We see our role [at Hill House] as creating a field hospital for this patient, if you like,” architect Andy Groarke told the Wall Street Journal recently.
Preliminary site work began last November, with two months of preparation for the installation of the structure’s steel frame of the structure. A 100-tonne mobile tower crane arrived on site on January 21 to lower into place the first steel beams of the box. The house and its gardens were closed while the giant box was being constructed, but they are now reopening to the public a week today. Visitors will not only be able to wander around the house, as before, but, by means of the elevated walkways that snake around the box and over the roof, they will be able to experience the property in an unorthodox way.
“Mackintosh was a pioneer and a visionary and we’re reflecting that spirit in our approach to saving his domestic masterpiece,” says Richard Williams, general manager for Glasgow and West at the National Trust for Scotland. 
“This is a project that has been many, many years in the making and it is wonderful to be at the point that we’re now seeing work begin to save such a significant place. What we’re doing here is a rescue plan for the long term and will, we’re sure, protect this incredible building for future generations.”
Extensive infra-red thermographic (IRT) imaging, carried out in 2013 and again this year, showed the full extent of water damage to Hill House. The newer images were combined with new 3D digital survey and microwave moisture readings.
“These surveys reinforce what we already knew about the house, which is that it is very damp and has considerable issues that need to be overcome,” Williams said in March.
“Due to the design of The Hill House, there are many ledges, wall heads and chimneys that have had a history of many attempts to remedy, yet this problem continues. We also now have additional areas of concern, such as large sections of harling that have become disengaged from the walls where damp is accumulating, and internal walls we hadn’t realised were so damp.”
The problem with rain penetration goes back to the handover of the house in 1904, says Simon Skinner, chief executive of the National Trust for Scotland.
“In the archives, there are notes about the chambermaids having to position buckets when it rained heavily. I think the house has leaked right from the outset, as far as we can tell, and when the trust took it over in 1982, there were a number of interventions and attempts to try to stop the worst of the water penetration.
“If you look at the design vernacular of the Victorian era and even into the Edwardian era, the general aim was to have coping stones placed over gable ends, and to heavily implement guttering. But Mackintosh didn’t do any of that. And when you add to that the fact that he was moving away from what we know works very well in the west of Scotland in terms of lime mortar, he introduced a brand-new material, a harling to cover the walls’ exterior, Portland cement.
“That’s been the downfall of the building, really. It has never really been able to stand up to the Scottish west coast weather, and has let in moisture right from the start.”
Skinner’s own background is a diverse one - his previous jobs have ranged from being director of procurement for Saudi Arabia’s military hospitals programme to senior corporate roles in the UK, including the position of chief executive of Aegon Ireland plc, an international insurance business. In a way, a certain gap in his skills-set turned out to be quite useful in the context of Hill House.
“I joined the Trust in 2015 and sadly I have very little conservation experience but that proved to be something of a benefit because it enabled us to step back,” he says.
“The Trust had, with other agencies and a lot of experts, been contemplating and debating for some years how we might start intervening in the building to try to protect it, but nobody was looking at the obvious.
“I used to live across from Helensburgh, in Bridge of Weir, and I was aware of the rainfall. There were 197 days of rain last year, and so, even if you call them ‘soft’ days, that’s a lot of rain. It struck me that the obvious answer was to somehow construct something that would keep the rain out but allow the building to breathe and to dry out naturally, and buy us some time.
“That concept was then developed, and Carmody Groarke, and Andy Groarke, were the people who won the contract to erect the mesh box. There had been other ideas for Hill House,” he adds. “Wrapping it in plastic, or putting glass around it, etcetera. 
“But all of these interventions failed to enable us to conserve the building and at the same time continue to engage with the public, allowing people to see the house and to climb over it and witness the changes that will be made over time, as the box allows us to do. Because it will take time while we try to intervene at Hill House and find out the best way forward.”
The Trust, then, faces an imposing challenge: keeping the rain out of the Mackintosh building, allowing it to dry out, repairing the damage caused by decades of water penetration and conserving all those delicate little Mackintosh touches.
“Yes, there is a lot on our plate, but to be honest that’s the excitement of all of this,” Skinner says.
“The Getty Foundation gave us close to £100,000 back in 2015 because they recognised that this isn’t just about the National Trust for Scotland’s property - this is true of many of the more avant-garde and more recent, particularly concrete buildings. “So if we can find a way of buying time, and then, through investigations with Historic Environment Scotland and others, find a solution to the building, then that will be of international significance, as well as across the rest of Scotland.”
The chainmail surround has already excited interest overseas, primarily from the United States. Some agencies that receive funding from the Getty Foundation have already contacted the Trust to ask about the box. The total cost of the project at Hill House is £4.5 million. A public appeal raised £1.5 million, most of it from Scottish members of the trust. Other funding came from the organisation’s own US foundation, and from its Patron's Club - the Trust's Patron is Prince Charles.
The rush of donations speaks to the esteem in which Mackintosh is held, 91 years after his death. His buildings are highly regarded, too: in the case of Hill House, Brad Pitt, a keen architecture enthusiast and his then-wife, Angelina Jolie, visited the place in 2011, while he was shooting a film, World War Z, in Glasgow in 2011. (Retail manager Karen Fenwick told The Herald after the visit: “They had a cup of tea and spent some money in the gift shop on Mackintosh things and some novelty pencils for the children. It was fantastic.”)
It’s also worth acknowledging the fact that Hill House is receiving so much protection not long after Mackintosh’s superb Art School building in Glasgow city centre suffered another catastrophic blaze last year.
“First of all,” Skinner says, “that [the fire] was a tragedy. Hopefully we have learned from that. There was no hot-flame construction in this site [at the Hill House box], and it was all bolted together, and because of that, it is wholly recyclable.
“The spooky circle here is that Mackintosh came to the Blackies’ attention when he had just finished the Art School. It was his masterpiece, and it excited the Blackies in a way.
“Mackintosh and his wife Margaret wanted to come and meet the family and understand how they lived. Charles and Margaret - who was, of course, also an artist - started on the building from the inside out. 
“One of my favourite quotes concerning Hill House came from Andy Groarke himself. He was looking at the house one day and he said, ‘It has fundamental mistakes in the very DNA of its construction’. But it is a beautiful building, inside and out.”
Skinner is evidently struck by the chainmail box that has been erected around Hill House. “The beauty of the material,” he says, “is that you can light it, and that rain runs down it. We will be lighting it, too, and trying to show the house.
“For me, it enables you, when you go in as a member of the public and walk up and over the catwalks, to see through it. It gives you that light, and it will let the house dry out.”
In terms of the water damage, assessments are being carried out to see how much of it can be naturally dried and how much can be repaired and replaced.
“It would not be an understatement to say Hill House is one of the jewels in the trust’s crown, if not the actual jewel,” he concludes. “It represents all that the Trust stands for, the conservation and preservation of Scotland’s heritage.
“And to see that being done in action will, I hope, spur more people to come and support us. We have a massive portfolio and we struggle, like all the historic agencies, to try and protect these buildings as well as the natural landscape of Scotland.
“Undoubtedly, some of our other properties could benefit from the approach being taken at Hill House, particularly where we need to dry out elements of buildings, whether those are tenth-century castles or not. More appropriately, this is pointing to our next challenge in Scotland - that wave of modernism that came in after [Hill House]. If you look at the early concrete constructions, we get a lot of problems with that.”
First things first, though. For the time being, Skinner and his colleagues are looking with abiding interest at Hill House.
“When Mackintosh was building Hill House he was signposting modernism at the end of the Victorian era and using revolutionary materials,” he says.
“I like to think that if he were looking down on us, he would be admiring the fact that we are doing the same thing, and the economy of the box - its form, function and decoration - all coming together.”
“Our Trust president [Neil Oliver], who is much better with words than I am, referred to it as a ‘gossamer armature’, and he’s right. I think that is absolutely what we have created at Helensburgh.”