Top Flat, 29 Marlborough Buildings, City Centre, Bath

29 Marlborough Buildings forms part of a group of Grade II late 18th century terraced townhouses, some of which have since been subdivided into apartments, situated within the Bath City-Wide Conservation Area and World Heritage Site. It forms part of the wider, indicative streetscape setting of the Grade I Royal Crescent and the Grade II Royal Victoria Park. Due to its unbroken length and scale it dominates the streetscape with long, largely unobscured north-south views from Cavendish Road towards Lower Bristol Road. The principal street-facing elevation has retained a large degree of the terrace’s original, designed homogeneity with rusticated ground floor detailing and clean three bay façade, albeit with some later alterations such as 19th century porches and extension ‘stacks’. The proposed focus of works is at roof level, concerning the street-facing dormer windows.

In response to 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. Alterations are expected to be sustain or enhance the special architectural or historic interest of a listed building.

The existing windows appear to be later non-original additions due to the use of a casement window type. As such, replacement is considered acceptable in-principle and would result in no loss of historic fabric and a negligible impact on the special interest of the listed building.

The proposed location of the windows at dormer level would have a limited impact on the overall appearance of the building’s principal façade, where the windows are partially concealed behind the parapet. Public views of the dormer windows as part of the terrace are further constrained due to the building heights combined with the narrowness of the road through Marlborough Buildings. This part of the building is therefore attributed a lesser weight when considering the significance of the building’s appearance, and may be better-suited to accommodate retrofit, though these should still be sensitive to the particular material, architectural, and aesthetic qualities of the building and its terraced setting.

The installation of slimlite double glazing is welcomed in principle where this would improve the windows’ thermal performance with limited visual impact in comparison with more standard double glazed units.

Works would be considered to offer public benefit through energy efficiency improvements, though we maintain that any energy efficiency gains need to be considered from a holistic, ‘whole house’ perspective, which considers the ‘energy hierarchy’, including behaviour change and measures to reduce energy waste.

We note that the application appears to present replacement windows in a like-for-like casement style, which would replicate the appearance of the existing dormer windows. We highlight that this application could offer a beneficial opportunity to a reinstate a more traditional window appearance, fenestration, and profile (eg. multi-pane timber sash windows) that would reflect the traditional use of window joinery across both No. 3 and the wider Grade II terrace, and enhance the character and appearance of the Conservation Area.

There are some concerns regarding the proposed profile of the replacement units, as the proposed drawings and sections of the front windows appear to show the use of both through and applied glazing bars. The use of through or integral glazing bars would sustain the traditional construction qualities and authentic design associated with the special architectural interest of a listed building. The use of applied glazing bars, would not uphold the integrity of traditional craft used in the construction of historic buildings. By virtue of their non-traditional sash window construction, they 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 and group value of the wider listed terrace.

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 not be outweighed by the harm to the special architectural and historic interest and significance of the listed building, and would detract from the character or appearance of the conservation area.

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.