Since it was built more than a century ago, this Helensburgh landmark has been absorbing the rain, putting the building and its unique interiors at risk. Now the conservation charity is surrounding the building with an innovative chainmail structure over the next six months, to protect it from the elements.

This semi-permeable metallic mesh pavilion, designed by architects Carmody Groarke, will allow the building to dry out over a number of years. In doing so, further conservation work can be commenced to save the world-famous house for generations to come.

The Hill House was completed in 1904 for publisher Walter Blackie. His granddaughter, Ruth Currie, broke ground on the site yesterday using a specially-created spade which echoes Mackintosh’s Hill House Ladderback Chair. She was joined by Andy Groarke of Carmody Groarke.

The house and gardens will be closed to the public during the construction of the ‘Box’ but are expected to reopen in late spring 2019, complete with new raised walkways around the exterior of the house and over the roof. These will give visitors a completely new way of experiencing the Hill House and Mackintosh’s design, as well as offering stunning views over the Clyde estuary. A community hut will also be open on site regularly over the winter, giving visitors the chance to drop in and see how the build is going.

Richard Williams, general manager for Glasgow and West at the National Trust for Scotland, said: “Mackintosh was a pioneer and a visionary and we’re reflecting that spirit in our approach to saving his domestic masterpiece. 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.”

Thousands of people have already donated to the charity’s Box the Hill House campaign which launched in February 2018. So far £1.3 million has been raised, with fundraising continuing for the final £200,000 of the target.

Donations to the appeal can be made online.