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2 Feb 2022

The Hill House: what we’ve learned since the Box went up

A view inside the Hill House Box showing the walkways that rise beside and above the Hill House.
From inside the Hill House Box
The Hill House has been complete for 118 years. Situated in Helensburgh, it overlooks the Firth of Clyde. More than anything else, water has defined the building’s history.

On the West Coast of Scotland, the Hill House sees 190 days of rain a year. That means the roof has sluiced off over 22,000 days of rain across its life. When the Trust discovered the damage that water was wreaking on the bones of the building, a bold decision was reached. We placed the Hill House in a protective box to shelter it from the elements. What have we learned since then?

The good news is the Box is doing exactly what it was intended to. Since its completion in 2019, the chainmail protection has been effective in keeping the rain out: the Hill House is beginning to dry out. We learned this with help from Historic Environment Scotland (HES), who undertook thermographic and moisture content surveys. This insight into the health of the building was made possible thanks to funds from Getty.

The Box provides visitors with a unique perspective on this incredible house, and an opportunity to explain the complex story of the building and the conservation conundrums it contains with a new augmented reality app and exhibition onsite. We’ve also had the chance to open even more rooms to the public and give a fuller idea of how the Hill House functioned as a family home for the Blackies.

A unique bird’s eye view of the Hill House

Now, a few years on from the Box’s completion, the building is beginning to dry and we’re seeing other effects and challenges to deal with. The iconic white render on the outside of the Hill House, a cement rough cast, was chosen by Mackintosh as he believed it would be totally waterproof. Unfortunately, preventing water ingress in buildings is much more complex than adding a coating of ‘waterproof’ render. As we wrote about in a previous story, Mackintosh’s decision to omit traditional water management features on the building has led to a century of tweaks and changes to the Hill House. Some of these, combined with the rough cast render, have influenced the way that the building is drying out. The water which has soaked into the fabric of the building is trying to escape – but because of the concrete render, it can’t go outward. That means it is starting to find its way into the interior of the building, affecting the beautiful interior design, and the team is having to work hard to deal with that moisture.

Read more: Water damage at the Hill House

So, what’s next now that the Box is beginning to take effect? We will carry on monitoring the building’s dampness, and work to protect the interior design. The Box will continue to give visitors an interesting way to explore the building from new angles – as well as sheltering the Hill House from the elements.

We’ve got some really important decisions to make about the future of Hill House and what the next steps in our conservation journey will be, which we’ll be exploring in a future story.

The continued work to conserve and care for the Hill House is made possible, in part, thanks to the Getty Foundation’s Keeping It Modern grant. Since 2014, Keeping It Modern has supported 77 grant projects of outstanding architectural significance that contribute to advancing conservation practice.

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