First Floor, 1 St Mary’s Buildings, Lyncombe, Bath

1 St Mary’s Buildings forms part of a Grade II early 19th century residential terrace attributed to John Pinch situated within the Bath conservation area and World Heritage Site. 1-2 St Mary’s Buildings were subsequently rebuilt in the 1950s following bomb damage in the Blitz, resulting in the reconfiguration of No. 1 into residential flats with a new northern access. As such no historic fabric remains, but the dwellings were rebuilt in a matching style and form as to reinstate the appearance of the terrace as a whole. Both 1-2 St Mary’s Buildings are described as “careful rebuilds” by Historic England and therefore included within the Grade II listing designation. The terrace follows the steep south-north slope towards Wells Road with a sweeping, continuous cornice and parapet, and remains an attractive example of symmetrical, balanced form and design typical of Bath’s terraced typology. The terrace has retained its traditional multi-pane windows along the terrace, and these have similarly been replicated at 1-2 St Mary’s Buildings, although these have been reproduced with the addition of sash horns.

In the light of the declared Climate Emergency, BPT is generally supportive of retrofit measures that sustain or respect the special architectural and historic interest of a listed building; alterations are expected to be visually coherent with the character of the building, and the wider shared character of the listed terrace and surrounding conservation area.
The existing windows are dated to the 1950s and therefore would not constitute a loss of historic fabric. The opportunity for the replacement of non-historic windows with more thermally efficient equivalents is welcomed.

Within this context, sash horns are felt to be acceptable to ensure that the proposed first floor windows match the retained windows across the rest of the building.

We are supportive of the principle of slimlite glazing in this setting. However, this remains dependent on the use of quality detailing appropriate to the appearance of a listed building and the wider group value of the terrace. This can be achieved through the use of an appropriate style of glazing bar thickness and profile to ensure the timber frame isn’t overly heavy or blocky in appearance.

We have some concerns regarding the proposed glazing bar thickness and profile. The proposed ovolo and fillet profile appears to be fairly thick in the proposed window elevations, and the proposed sections show that the glazing bars would be thick and ‘shallow’ in profile. As a result, the glazing bars would be visually chunky and would not allow for an appropriate level of definition or detailing appropriate to the appearance of a listed building and the wider Grade II terrace. The meeting rails are too thick and appear to meet vertically, rather than featuring a more traditional angled meet. The proposed windows appear to be a standardised specification and are not tailored to the specific architectural interest of the Grade II building and its wider terraced setting.

It is additionally difficult to assess the suitability of the proposed windows without adequate reference as to the existing window detail. We encourage sections of the windows as existing to be provided to ensure adequate reference is being made to the existing appearance of the listed building and how this can best be sustained. Similarly, no reference is made to the wider context of the terrace and what sort of glazing bar profile is typical of the streetscape. Therefore, greater reference should be made to the existing fenestration style of the listed building and wider area to appropriately inform the proposed design.

Where the proposed window form is restricted to what is available from a particular supplier or manufacturer, we feeler that a broader consideration of what is currently available on the market is necessary to ensure that the bespoke qualities of the listed building are being sustained.

This proposal, if got right, could help provide an invaluable opportunity to monitor the thermal and acoustic efficiency of the windows, before and after, whilst also observing any additional repercussions such as changes in humidity levels. This information could then be used to more accurately assess the suitability of slimlite installation in Bath’s historic building stock.

BPT is very interested in working with the applicant to reach an acceptable solution and getting better understanding of the existing window condition and design.

Considering the difficulties of the fragmented occupation of the building as apartments, there is an opportunity for a collaborative cross-occupier scheme to replace all windows across the building with slimlite glazing. This would allow for wholescale energy efficiency improvements whilst ensuring the appearance of the building remained uniform. It would also allow for incongruous details to be addressed, such as the inclusion of sash horns on the 1950s rebuilt aspect of the terrace. However, we appreciate that this is not a matter for consideration as part of the current planning application.