How to minimise materials use in historic buildings
The team reused the substantial existing masonry walls, made of limestone from Bodmin Moor. This significantly reduced embodied carbon, cut construction costs and preserved heritage value. Around 9,000 tonnes of stone were retained and restored, employing local specialists in stone masonry repair.
Our structural interventions were lightweight wherever possible, avoiding the need for extra foundations. These included lightweight steel and timber balconies, replicating earlier balconies lost through years of exposure. We engineered a lightweight steel and glass roof for the atrium and a timber roof above the former jail wings, replacing earlier designs for a steel roof based on test findings.
Finding cost savings as a trusted advisor for our client
Throughout the five year project, Arup and Twelve Architects remained trusted advisors – from the complex planning submission and detailed design phase, through to the final opening. We worked alongside four contractors, two quantity surveying teams and two project management organisations.
Together with Twelve Architects, we value engineered tasks wherever possible, reducing construction costs and risks. Our atrium design, combined with glass maintenance strategies, avoided the need for gantries or secondary walkways, while the coordinated riser strategy avoided additional secondary steelwork and support to existing floors. Our approach to masonry openings made it possible to use off-the-shelf support lintels, rather than bespoke manufactured, and our MEP system eliminated roof level plant, simplifying the roof arrangement and allowing the use of standard timber trusses.