MONTHS of work to build a protective steel frame around the Hill House in Helensburgh are now under way.

A 100-tonne mobile tower crane arrived outside the visitor attraction on Monday morning to start work on erecting the first steel beams of the frame, which the building's owners hope will protect it from the ravages of the Scottish weather.

The frame – which the National Trust for Scotland (NTS) is calling 'The Box' – will completely enclose the building, with a solid steel roof and a chain-mail shield around the sides, to allow the Trust time to explore options for the long-term protection and restoration of the world-famous building, designed by Charles Rennie Mackintosh.

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The Hill House and surrounding gardens are closed to the public during the construction of the frame, but will reopen when the structure is complete – expected to be in late spring this year.

As well as protecting the building from the weather, the ‘Box’ will give visitors the chance to get a new perspective on The Hill House from elevated walkways looping around the building, and see conservation work on the Hill House in action.

The construction of the frame will cost £4.5 million, and a £1.5m fund-raising campaign launched by the NTS last year is already only £300,000 short of its target.

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Once the frame is complete, the Helensburgh landmark will be surrounded by a fine perforated mesh, designed by award-winning architects Carmody Groarke.

Richard Williams, NTS general manager for Glasgow and the west of Scotland, said: “Seeing the box take shape is an extraordinary feeling and a significant milestone in our charity’s rescue effort to save The Hill House.

"After years of planning we can really start to see the scale of what we’re doing here, for the love of the building and where it stands in the history of Scottish architecture.”

Donors to the Trust's 'Box The Hill House' campaign include the world-famous confectionery firm Tunnock's, who pledged a five-figure sum to support the project last year.

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Since it was built over a century ago, the Hill House has been absorbing the rain, putting the building and its unique interiors at risk.

The semi-permanent enclosure will provide shelter to the building, letting it dry out after years of disintegration and allowing for further conservation work to take place, while the metal mesh will allow the structure to continue to 'breathe'.

Donations to the appeal can be made online at www.nts.org.uk/Campaign/Help-us-save-the-Hill-House

In 2015, the Getty Foundation awarded a grant of £95,000 through its Keeping It Modern initiative to support the development of a conservation management plan for The Hill House.