A CONSERVATION group has launched a public appeal to raise £1.5 million in a bid to help save the landmark Hill House in Helensburgh.

The Advertiser reported in December that the Mackintosh mansion was set to be covered by a giant enclosure almost 60 feet tall for up to 10 years in a bid to protect the building from the weather.

The National Trust for Scotland (NTS) now estimates it will cost £4.5m to build the enclosure, deemed necessary to save the building from crumbling, and they are undertaking one their biggest fundraising drives ever to obtain the money.

The trust claims the transparent structure will protect the building from the elements, giving conservation teams the time needed to find long-term solutions to secure the building’s structural integrity.

An NTS spokesman confirmed £3m has already been secured from a variety of sources but another £1.5m is required to be “absolutely sure of saving the Hill House”.

He said: “For the first time we will be writing to all of our members to ask for their support, as well as working with colleagues internationally to ask for the balance of funds needed.

“Reaching the target will allow us to build a colossal shelter over the building and shield it from the biting west coast winds and driven rain. This in turn will give us the vital breathing space required to dry out the saturated walls and then find the long-term solution needed to prevent further damage.”

The plans, revealed last month, include a ramped walkway between the structure and the house, to give members of the public the chance to see the conservation work up close.

With 2018 being the 150th anniversary of Mackintosh’s birth, the trust is hoping to kick-start the year by securing the funds needed to save the landmark building.

The spokesman added: “The ‘box’ shelter will allow visitors to continue to enjoy the building while conservation and restoration work progresses and the temporary structure will provide a unique opportunity to get to rooftop level and examine the Hill House in detail.

“It will be a brave, innovative, cutting-edge model of conservation that will inform and inspire organisations across the world as more 20th century buildings become recognised as heritage that should be preserved for future generations.

“The Hill House is one of Mackintosh’s finest and most experimental designs – it very much influenced architectural design in the 20th and 21st century and was a true prototype for the way we live now.

“By saving it we can show how a Scot helped invent the future and also ensure generations of continuing public access to the Hill House for decades if not centuries to come.”

To donate, visit nts.org.uk/Donate/Appeal/Once/Help-us-save-the-Hill-House

A dedicated telephone number for donations will open when the appeal is formally launched later this month.