National Trust seeks £1.5m to protect Mackintosh's Hill House

The National Trust for Scotland (NTS) plans to build a huge transparent cage around the Charles Rennie Mackintosh designed Hill House, whose sandstone structure is dissolving.

The property was designed as a “home for the future” by Mackintosh between 1902 and 1904 but his choice of then relatively new material Portland cement for the render led to problems as it has allowed water to soak in from the day it was first applied.

Decades of wind and rain have saturated the walls, threatening the long-term ­survival of the property in Helensburgh, Argyll and Bute.

Debbie Crosbie of The Clydesdale Bank with Richard Williams of The National Trust for Scotland at The Hill House in Helensburgh, designed by Charles Rennie Mackintosh

The trust has already secured £3m towards the construction of the box but needs another £1.5m by the end of spring this year to reach the overall target.

Richard Williams, general manager for Glasgow and West at NTS, said: “This is one of the most urgent and important appeals in our history. We have very limited time to get the box in place around the Hill House and start the process of drying the building out.

“It’s imperative that we secure the funds as soon as possible, to begin construction and protect the building from further degradation.

“The box shelter will also allow visitors to see the building from a completely new perspective, with walkways and an opportunity to get to rooftop level.”

Debbie Crosbie of The Clydesdale Bank with Richard Williams of The National Trust for Scotland at The Hill House in Helensburgh, designed by Charles Rennie Mackintosh

Assembly of the box is expected to begin in June this year, protecting the property from another winter.

Supporting the launch of the Box: The Hill House Appeal, CYBG, owner of Clydesdale Bank, has donated the original printing plate used to produce its £100 note, which features Charles Rennie Mackintosh.

The plate was used to print 200,000 notes, which entered circulation in 2009.

The plate and a £100 specimen bank note have been mounted in a presentation frame and will be auctioned off later this year with all proceeds going towards the campaign.

This weekend, every NTS member will receive a letter asking them to support the appeal.

The cage – designed by architects Carmody Groarke – will keep out the elements while conservationists come up with ways to protect the house for the long term. The building will remain open to the public while conservationists are at work.

Born in 1868, Mackintosh trained as an architect and went on to create buildings including the Glasgow School of Art and Scotland Street School in the city.