13 Caroline Buildings, Widcombe, Bath

13 Caroline Buildings forms part of a Grade II early 19th century terrace of townhouses at 1-20 Caroline Buildings, situated within the Bath conservation area and World Heritage Site. The terrace remains largely homogenous and well-balanced in appearance with a three bay frontage in Bath stone ashlar; each house is comprised of a pair of sash windows across the ground, first, and second floors and a raised keys and surround arched front door reveal. The terrace enjoys an elevated position over Pulteney Road (South) with access from a raised flag pavement, separately Grade II listed. It backs onto the Kennet & Avon Canal towpath to the south-east with high visibility in mid-range elevated views from Abbey View Gardens. A large number of the houses retain their original-style 6-over-6 timber sash windows, although later replacement and alteration have resulted in a mixed variety of window styles which somewhat unbalances the terrace’s otherwise uniform appearance. 13 Caroline Buildings retains its traditional-style 6-over-6 sash windows, although these are dated to refurbishment works in 2006 and are therefore do not constitute historic fabric.

We are disappointed by the retrospective nature of this application and maintain that the appropriate consent should always be appropriately obtained before works commence.

In light of the declared Climate Emergency, BPT is supportive of sensitive sustainability retrofits, where deemed appropriate, within the historic environment, as well as the sympathetic upgrade of traditional and listed housing stock to better meet modern standards of living.

The existing windows are indicated to be 2006 replacements and in poor condition; as such, this is a positive opportunity for the sensitive implementation of energy efficiency retrofits and thermal improvements where this would not result in loss of historic fabric.

We therefore welcome the opportunity for the installation of slim double glazing. As existing, there are very few examples of ultra-slim double glazing such as vacuum glazing being used in Bath, with a similar scheme at 12 Hanover Street recently granted planning consent being one of the few comparable examples. There would be an exciting opportunity to trial this technology, with potential benefit for future window retrofit with an increased thermal performance and reduced visual impact.

However, we note that the technical specifications of Fineo glazing includes reference to the use of “20 mm grid micro-pillars” between the individual glazing panes, which may result in the windows having a ‘speckled’ appearance and detract from the overall appearance of the listed building. From the photos provided of the windows as installed, the micro-pillars are faintly visible in close-up views, but further assessment is required as to their visibility in public views from the pavement, particularly within the wider context of the terrace and neighbouring windows. BPT would be very interested in engaging further with the applicant with the possibility of a site visit to see the proposed vacuum glazing in situ.

However, we regret that we are unable to support the use of applied glazing bars, rather than traditional through glazing bars, which would be an incongruous visual and material addition across the principal façade of a listed building. This would result in adverse impact to the established fenestration style and traditional construction not only of the building, but the integrity of the wider listed terrace.

Whilst we recognise that the D&A Statement cites that through glazing bars are not feasible due to the required thickness of the seal rebate (10mm), two recent examples of proposed multi-pane sash windows with vacuum glazing at Hanover Street and to the rear of the Circus indicate the use of through glazing bars, although this may necessitate glazing bars of a slightly increased thickness. As such, there remains some uncertainty as to the viability of through glazing bars when considered against other similar listed building proposals.

We recognise that there are identifiable public benefits in the installation of slim double glazing and the associated contribution this would make towards the adaptation of our historic building stock to meet the challenges of climate change, as well as their sustainable future use. However, we consider that this would be outweighed by the harm to the special architectural and historic interest of multiple listed buildings, and would not preserve or enhance the character or appearance of the conservation area.

We maintain that the use of applied glazing bars would result in harm to multiple heritage assets, contrary to the Planning (Listed Buildings and Conservation Areas) Act 1990, Section 16 of the NPPF, and Policies B1, D, D2, D3, and HE1 of the Core Strategy and Placemaking Plan. We strongly recommend that this aspect of the scheme is suitably amended.