Rosslyn Castle, jointly with Rosslyn Chapel, is one of the most significant heritage assets in Midlothian. Surrounded on three sides by the river North Esk, the Castle is located within the magnificent wooded Roslin Glen, the largest surviving tract of ancient woodland in Midlothian.

The A-listed building known as the East Range, which dates back to the 16^th century, has remained partly ruinous since the mid-1600s. The project provides a new permanent roof over ruinous areas of the East Range for the first time in over 350 years, bringing the spaces back into use and safeguarding the historic fabric for future generations. Along with an extensive programme of conservation and repair works to the building, three layers of medieval vaults below the ground floor have also been repurposed, now housing new air source heat pumps making the castle Net Zero Ready.

The project was fully funded by the Rosslyn chapel Trust, a charity established in 1995 by the current Earl of Rosslyn. The Rosslyn Chapel Trust oversee the full Rosslyn precinct and are responsible for the care and maintenance of the various buildings within the grounds.

The Rosslyn Chapel Trust commissioned Page\Park to implement their vision to conserve the Great Hall, adjoining tower area, and the three layers of medieval vaults below, which were dramatically deteriorating due to their exposure to rainfall for the past 350 years. The East Range operates as a holiday let in partnership with the Landmark Trust and income generated from the holiday accommodation is used to help look after the full castle complex.

Architectural Concept

The A-listed building known as the East Range dates back to the 16^th century and sits within a Scheduled Monument covering the surrounding areas. Overall the aim of the project was to carry out a comprehensive scheme of conservation works, making it more resilient in the context of climate change and increased rainfall having been partly ruinous from the mid-1600s. This was achieved through a new permanent roof over previously ruinous areas of the East Range, covering and protecting these areas along with highly significant carvings inside for the first time in over 350 years.

The decision to reroof the castle was born out of a conservation management plan Page\Park undertook for the entire area, with one of the primary outcomes being to aid not only the long term management of the castle but also its setting. The conservation-led approach to the project sought to minimise any visual impact on the historic setting whilst upgrading the castle and bringing it up to 21^st century standards.

Through the early stages of the design process, various options for the best approach to conserving and protecting the vulnerable masonry were considered through collaboration with the council and Historic Environment Scotland. Options included conservation of wall heads only, light-weight structures, and the reintroduction of a permanent roof. The latter option was agreed as being the most appropriate and future-proof approach, allowing for a more holistic and sustainable project to be undertaken. A key aspect of the client brief was to ensure the new and old spaces were well heated, creating a more comfortable holiday accommodation where the 17th century and modern living experiences can harmoniously coexist.

Externally new elements were designed to subtly blend in with the existing form and be sympathetic to the existing materials, despite being purposefully distinguishable from the historic fabric on close inspection. The structure of the roof is expressed internally through exposed douglas fir rafters and linings, which echo the existing roof construction elsewhere in the building. Hidden from view on arrival, on the west gable, new curtain wall glazing juxtaposes the existing stonework with a modern intervention, opening up views to the ancient woodlands surrounding the castle. From the surrounding Glen below, the new glazing offers a glimpse of a new stone fireplace used to conceal structural supports for the new roof and introduce a new focal point in the ‘Great Hall’.

New interiors were designed to be contemporary and not as a reconstruction of the historic interiors, with high quality natural materials used throughout to age well and develop patina over time. An exciting aspect of the project was the level of craft involved, to create bespoke designed elements which complement the rich palette of materials while emphasising existing masonry carvings of exceptional significance.

Sustainability

An important part of the project is the addition of new air source heat pumps located within the medieval vaults, making the castle Net Zero Ready. These vaults date back to the 16^th century, meaning it is possibly the oldest building in the world to have adopted air source heat pumps as a sustainable, low carbon technology. Historically used as service spaces, the vaults provided kitchens, bakehouses, and dungeons, these spaces are now revived once more as modern-day service spaces operating as plant rooms.

The cutting-edge heat pump technology and historic stone vaults co-exist in a symbiotic relationship, both benefitting from each other, with the thermal mass on the masonry maintaining a consistent temperature within the vaults, maximising the heat pumps efficiency. This makes the Rosslyn Castles sustainable heating system unique when compared with conventional air source heat pump installations.  Air movement is also aided by the heat pumps and plant, which helps dry out the masonry, justifying the radical positioning of this innovative technology.  To help maximise the efficiency of the heat pumps and to provide resilience to the system, thermal stores have been provided as part of the design, acting as thermal batteries being charged by the heat pumps. By incorporating the thermal stores, it was possible to reduce the capacity of the heat pumps to work within the confines of the available electrical supply, which also aims to lower energy bills for the client.