Rosslyn Castle in Midlothian, which sits close to the famous chapel, is set to undergo a major programme or repair and renovation.
Built by the St Clair family, the oldest parts of Rosslyn Castle date back to the early 14th century, with the fortress bearing witness to several turbulent periods in Scottish history.
The East Range, a domestic residence built in the early 1600s, lies partly in ruin with the roofless Great Hall and Tower increasingly vulnerable to weather damage.
Currently used as a garden area, the East Range will now be covered with a permanent roof to create a new habitable space for holiday lets and protect the impressive three-storey basement – previously used as a bakehouse and store – from further deterioration.
Ian Gardner, director of Rosslyn Chapel Trust, said: “This proposed project will help to prevent the further deterioration of important parts of the castle’s East Range, both above and below ground, which have suffered from continuous water ingress over centuries.
"It will also improve the quality of the experience for guests staying here and secure the long-term future of one of Midlothian’s most historically significant buildings.”
Plans for the renovation of the Grade A listed building and schedule monument have now been put forward to Midlothian Council and Historic Environment Scotland by the Rosslyn Chapel Trust.
Part of the East Range is already used as holiday accommodation for six people, with the restored building to offer more room for guests, as well as a kitchen area and living area.
Rosslyn Castle suffered serious fire in the 15th century, severe destruction in the 16th century during the ‘Rough Wooing’ of Henry VIIIs forces and further attack by the Cromwellian army, led by General Monk, in the 17th century.
Mr Gardner said the latest threat to the castle’s historic fabric was now coming from climate change and increased rainfall.
The roof will now protect crumbling masonry carvings and a fireplace in the former Great Hall, as well as shield the vaults below, which have been filling up with water.
Pointing and erosion will also be fixed on the south elevation, with a whole new sustainable heating system to be installed.
Rosslyn Castle is category A-listed, recognising its architectural and historic character and its grounds are designated as a scheduled monument.
The castle is in the care of Rosslyn Chapel Trust and has provided self-catering accommodation, through a partnership with The Landmark Trust, since the 1980s.
Karen Nugent, of Page\Park architects, who has been working on the restoration project, said: “It is unusual that a ruin and habitable house co-exist within the same footprint of a bigger building and, through this work, we will reintegrate both elements, following guidelines of leading conservation bodies in Scotland, the United Kingdom and Europe.
"We are delighted to be appointed to work on this exciting project, which will bring enormous benefits to the building for generations to come."