The Hill House: a century of change

Built for the Blackie family, the architect Charles Rennie Mackintosh designed the building while his wife, Margaret Macdonald Mackintosh, created the interiors. When it was completed, Mackintosh told Walter Blackie: ‘Here is the house. It is not an Italian Villa, an English Mansion House, a Swiss Chalet, or a Scotch Castle. It is a Dwelling House’.

The fact that the Hill House is first and foremost a family home really sets it apart as a Mackintosh creation. Stepping into it feels like time travel – the glamourous style is straight from 1900. However, all is not what it seems. While the classic style and design of the Hill House appears to be totally pristine, as if the building has been perfectly preserved through the last century, this isn’t the whole story. In fact, the Hill House has been almost constantly adjusted, altered and amended throughout its history.

First was Mackintosh. He was using new materials in experimental ways when building the Hill House. He was determined to create a uniform aesthetic by using cement-based roughcast in a way that led him to skip the addition of traditional architectural features designed to deal with rain. Because he was experimenting, he made several changes and tweaks to the design of the house before finally handing it over to the Blackie family in 1904, and indeed afterwards too.

Dealing with rain and water would be a continuing theme for the Hill House. In the 1950s the then owner of the house, Campbell Lawson, brought in leading architect Margaret Brodie. Margaret made some big changes to the building to attempt to stop water from getting in. She changed the appearance of the roof, removed the main chimney and added weathering features to combat the harsh west coast weather – interventions which were all, ultimately, unsuccessful.

In the 1970s the Royal Incorporation of Architects in Scotland (RIAS) brought in Gillespie Kidd & Coia to restore the Hill House. They were keen to re-establish Mackintosh’s features as much as possible, restoring the original look and design as faithfully as possible. They undid the changes made by Brodie and rebuilt the chimney. They also repaired the problematic roughcast.

By the 1980s, the National Trust for Scotland had taken over the care for the Hill House. Another architectural firm, Boys Jarvis, came in to do more repairs. They removed more failing roughcast and ‘cloured back’ the stone beyond, which had degraded over the decades. They rebuilt in brick, removing much of the historic fabric and repairing large areas of the roughcast. After concerns raised by the authorities about this repair approach, architects Page & Park came in during the 1990s. They were much more focused on preserving what was already there, rather than losing original materials and altering the Hill House. They pinned the older roughcast to the building and also applied salines and polyester resins beyond the roughcast to aid this approach, introducing a whole new range of materials to the mix.

This approach was deemed successful in the years immediately after these works. However, as part of the National Trust for Scotland’s ongoing programme of condition surveys, concerns were raised in the early 2000s about the current state of the house. These surveys were complemented by infra-red thermographic surveys, which helped determine how the walls of the Hill House function beyond the roughcast finish.

More recently, an infra-red thermographic and micro-wave moisture survey, mapped onto a digital model, created a detailed 3D picture of the Hill House. The National Trust for Scotland now had a complete picture of the health of the property. Decades of rain had soaked the building and caused damage to the bones of the Hill House. A bold strategy was decided – the Trust would place the Hill House within a chainmail box to protect it from the elements.

Thousands of years ago, the Ancient Greek thinker Plutarch created a thought exercise called ‘the ship of Theseus’. The philosopher asks: if you replace the sails, repair the hull, change the oars of a boat, at what point does the ship cease to be the ship of Theseus and become a brand-new ship? We can apply this thinking to the Hill House too. With so many changes and alterations over the years, which version of the building is the ‘real’ Hill House? Which version should be preserved or restored? These are the complex questions that those working in modern heritage must consider, and exactly the dilemmas our conservation charity faces, as we plan what’s next for this incredible, iconic building that must be protected now and for future generations.

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.