After a busy two years of liaison with the Local Authority, National Amenity Societies and stakeholder groups - we are pleased to announce that Full Planning Permission and Listed Building Consent have been achieved for our proposals at Bath Assembly Rooms.
With a Grade I listed building of the utmost sensitivity, and an appropriately ambitious brief to refurbish and decarbonise the site, the process of iteratively presenting and reviewing proposals with the Local Authority has been patient, thoughtful, and ultimately incredibly rewarding. The Case Officer’s Delegated Report summarised the process similarly:
“The proposals have benefited from a detailed, careful, informed and commendable collaborative approach. The historic building has been thoroughly and comprehensively assessed, analysed, and understood. This approach will result in significant heritage benefits, both in terms of physical and visual, but also arising the emphasis of the historic building itself as the point of interest for the community and visitors alike. Its significance will be better revealed and its architectural legibility will be increased as a result of the proposals. These heritage benefits are positive for the listed building, the conservation area, and the UNESCO World Heritage City.”
A primary component of the proposals is the proposal to cease the use of fossil fuels on the site by replacing the existing gas boiler infrastructure with new air source heat pump technology. This has been particularly challenging within this tight city centre location with minimal external space within the site boundary. Resolving this meant working closely with Max Fordham LLP to assess multiple options for potential plant at roof level, and ultimately concluded with the proposal for an array of 26 individual domestic scale pumps working in synch to meet the demands of the cultural venue.
John Wood the Younger’s design for the massing of the Assembly Rooms is a masterpiece of urban architecture – establishing 3 triple-storey ‘blocks’ (forming the Ball Room, the Tea Room and the Great Octagon) that respond to the scale and arrangements of their respective streets (Bennet St, Alfred St and Saville Row respectively). This distinctive form offers the opportunity to site the majority of the pumps in the centre of the site, above the low single-storey connecting link, where they can nestle down behind the west entrance portico and be unobserved from any of the surrounding public realm.
Crucial to the proposals for switching from gas to the low-temperature ASHP system is paying attention to heat-loss – with a high priority target being the existing single glazed sash windows, of which there are over 100. Our research in the archive and investigations on site confirmed the anecdotal evidence that almost all of the existing windows dated to the 1950s restoration works following the war time damage, and those few that did survive were likely to date to the comprehensive restorations of the 1930s. We were able to demonstrate that the primary significance of the windows was their aesthetic contributions to the elevations and interiors, rather than the evidential value of their physical fabric. Following this agreement of principles, we worked closely with suppliers and craftspeople to demonstrate the suitability of a vacuum sealed slimline double glazed unit (achieving the thermal performance of a triple glazed casement in just 7mm thickness) – including the procurement of a prototype sash to discuss on site with local and national stakeholders.
Through an open and iterative dialogue we were able to demonstrate that the visual impact of this technology on the site’s aesthetic significance would be negligible, whilst the public benefit of decarbonising the site and setting new bench-marks for low-energy heritage were deemed to be considerable. Due to the scale of the site the proposed joinery upgrades will be implemented in a sequence of phases over the coming years.
The journey to achieving statutory consents has a reputation for being arduous, particularly for listed buildings – but in truth it is a part of all of our projects that we really enjoy. The opportunity to debate proposals – from the philosophical values of a site and its future down to the fine detail of a new physical fixing into an existing element – with enthusiastic, engaged and learned consultees is often a privilege and a pleasure. This last year of consultation for the Bath Assembly Room project has been a great example of this, and we want to thank the teams at BANES, Historic England, Georgian Group, Bath Preservation Trust and Transition Bath particularly for their passionate and knowledgeable contributions.
Charlie