Courtesy Carmody Groarke

On Dec. 6, London-based architecture firm Carmody Groarke and the Scottish conservation organization National Trust for Scotland revealed plans for the conservation of the Hill House, an early 20th-century mansion located in Helensburgh, Scotland.

Designed by late Scottish architect and designer Charles Rennie Mackintosh, the Hill House was built in 1904 for Scottish publisher Walter Blackie. Today, more than a century after its completion, the house remains one of Scotland's most significant buildings and one of Mackintosh's best works. The mansion features a façade free from architectural details common to the Victorian and Edwardian styles of the late 19th and early 20th centuries. According to the Trust's website, Mackintosh specified Portland cement, a new type of material that had just become available on the Scottish market. Although harling was a common finishing and weather-proofing technique in Scotland, Portland cement was not compatible with the humid weather of the Scottish west coast. As a result, the façade's long-term survival is under threat from moisture that is brought in from the house's close proximity to the sea.

Courtesy Carmody Groarke

Carmody Groarke's design would cover the historic mansion with a semi-transparent enclosure made of perforated mesh. The outer shell will protect the house from wind, rain, and humidity but still allow air to circulate, which will help the building to dry faster. Inside, elevated walkways and viewing points allow visitors to watch the restoration work in progress and have a closer look at Mackintosh's design.

“The National Trust of Scotland are adopting a very bold approach to the conservation of the Hill House; one that is radical and experimentative in seeking new methods to extend the life span of our heritage, and one that invites public interaction and interpretation of these processes," said Carmody Groarke's founding partner Andy Groarke in a press release. "We are very proud to play a part in this pioneering project of theirs and to have a chance to learn at first-hand about Charles Rennie Mackintosh’s residential masterpiece.”

An estimated budget of £4.5 million (approximately $6 million) is needed to complete the conservation work. The structure is planned to be installed next year and the conservation work is estimated to take about 12 years to finish.