THE owners of Helensburgh's leading visitor attraction say they hope to announce their plans for the future of the property within weeks.

The National Trust for Scotland warned last year that repairs to the Hill House were likely to cost millions of pounds.

The Trust confirmed this week that London-based architecture studio Carmody Groarke had been engaged to work on its Hill House Conservation Project.

Details of that project are set to be announced soon – but the Trust is hoping that its work on the Hill House, admired around the world as one of the finest examples of the work of Charles Rennie Mackintosh, will give guidance to other organisations faced with the problem of restoring and preserving their own historic buildings.

An architecture industry journal announced this week that Carmody Groarke had been chosen to design a new temporary vistor centre for the Hill House – but the Trust quickly moved to correct that announcement, stating that while its original proposals for the house had indeed included a temporary facility, the organisation was now in the process of putting together “a different approach”.

An NTS spokesman said: “Hill House is one of Scotland’s most important buildings, essentially helping to set the blueprint for what we regard as modern architecture.

“It is a challenging building to manage and conserve – indeed, many organisations across the world have their eyes on what we are doing here as relatively few buildings that have employed similar ‘modern’ construction techniques had been subject to full scale restoration and preservation. 

“As we move further into the 21st century, many more buildings from the last 100 years are going to receive heritage status and the problems we see at Hill House will have to be tackled elsewhere.

“It is well-known that Mackintosh’s use of then cutting-edge Portland Cement exterior finishes allowed moisture ingress more or less from day one. 

“Given the building’s location in the west of Scotland, this is a problem that has to be solved and we are working towards innovative solutions that we hope will allow us to do that.”

The philanthropic Getty Foundation has already made a contribution of £95,000 towards the long-term conservation works – without which, experts say, major problems with some of the building's internal features are likely to become evident within a few years.

In his design for the Hill House, built for the publisher Walter Blackie and completed in 1904, Mackintosh dispensed with many techniques normally used to protect buildings from the effects of bad weather, such as projecting chimneys and skew copes, in order to achieve his aim of a house devoid of “adventitious ornamentation”, hoping instead that a cement-based harling – in those days a relatively untried technique – would weatherproof the most vulnerable areas of the building.