Internal and external alterations for the enlargement of the rear single storey extension. Replace UPVC windows with timber sash windows to the front elevation and triple glazed aluminium casement windows…
Our Response

1 Dafford’s Buildings is a Grade II early to mid-19th century two storey terraced house situated within the Bath conservation area and World Heritage Site. It forms part of the indicative streetscape setting of a high concentration of Grade II terraced dwellings along Dafford’s Buildings that vary in age from late 18th century to mid-19th century. The terrace additionally backs onto the Grade II early to mid-19th century terrace at Dafford’s Street and the adjoining Grade II Larkhall Methodist Church. The terrace is predominantly 2 - 21/2 storeys in height, stepping up to 3 storeys at the northernmost end, and displays some variety in façade width, articulation, and finish. A large number of properties have been painted, but the principal building material is Bath stone ashlar, albeit with some adjacent later builds in reconstituted stone, which is reflected in traditional examples of boundary walling in the area. 1 Dafford’s Buildings is an example of one of the more modest, double depth houses that shares a running parapet level with the neighbouring 3-4 Dafford’s Place, and has undergone a number of unsympathetic later alterations with detriment to the special architectural and historic interest of a listed building.

In principle, BPT is supportive of sensitive sustainability retrofits, where deemed appropriate, within the historic environment. Our position in a relation to the appropriateness of a range of measures is set out in our publication Warmer Bath: A Guide to Improving the Energy Efficiency of Traditional Homes in the City of Bath. In light of the current Climate Emergency, we appreciate the urgency of reducing energy consumption and carbon production, as well as upgrading our existing historic housing stock to meet modern standards of living and thermal performance.

However, we maintain the suitability of energy-efficient retrofits in relation to heritage significance, effectiveness, and the risk of unintended consequences must be assessed on a case-by-case basis.

BPT is supportive of the principle of the proposed installation of timber sash windows, which would reinstate an aspect of traditional detailing to the benefit of the appearance and special architectural interest of a listed building. However, we are concerned regarding the proposed insertion of what appears to be standard double glazing in the principal elevation of a listed building without appropriate consideration or assessment of the potential detriment to the appearance or significance of a listed building. Standard double glazing is typically more unsympathetic to the character of a listed building due to its chunkier profile and ‘double reflection’. We therefore strongly recommend that any double glazing in the front elevation should be slimmer profile 14mm glazing as a more sensitive alternative.

We consider that the proposed aluminium framed casement windows in the rear elevation would be less visually harmful than the existing uPVC windows. However, it is unclear as to why a casement design has been selected, and we maintain that a timber sash window design would be significantly more sympathetic to the original appearance and character of the listed building.

We have some concerns regarding the proposed insertion of triple glazing in the existing window reveals in the rear elevation and suggest that further information is supplied regarding the proposed thickness of glazing in comparison to the existing reveals to ensure the windows would be able to sit appropriately within the reveals. A flush finish would not be appropriate.

With regards to the proposed repainting of the front elevation, we strongly recommend that further details are provided regarding the proposed paint colour and finish to ensure a complementary appearance. A number of other houses on the terraces have opted for an off-white or cream finish which may be more appropriate.

We additionally highlight the particular historic interest of 1 Dafford’s Buildings’ principal elevation in the retention of a historic street sign on the first floor, now eroded and barely legible. We strongly recommend that further details are provided regarding how this signage would be retained as part of works, and if there are any plans for potential restoration works to a historic street feature of interest to the appearance and character of the conservation area.

BPT has some concerns regarding the proposed application of external wall insulation to the rear elevation. Whilst we note that the existing elevation drawings indicates that the rear elevation has been rendered, we maintain that there is insufficient information regarding the current appearance or condition of the rear elevation and its wider contextual setting as part of a Grade II terrace. There are additionally no material specifications provided regarding the proposed type or depth of the selected external insulation, or how it would be secured. Due to the required thickness of external wall insulation, this results in an increased depth around details such as window reveals and would push the elevation forwards out of line with its neighbours, with consequent harm to the aesthetic relationship between multiple listed buildings. There are some practical concerns about how the increased depth of the rear elevation would interact with the rear roof eaves and whether this would necessitate further alterations with resulting visual impact to a listed building. We therefore maintain that further details are required to enable a proper assessment of the works proposed and potential impact to the appearance and character of a listed building.

We encourage the inclusion of less invasive internal insulation as part of works such as loose-fill loft or (where appropriate) underfloor insulation.

BPT is very interested in working with the applicant to reach an acceptable solution. This proposal, if got right, could help provide an invaluable opportunity to monitor the thermal efficiency of retrofit measures, 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 measures in Bath’s historic building stock.

Application Number: 21/03153/LBA
Application Date: 02/07/2021
Closing Date: 05/08/2021
Address: 1 Dafford's Buildings, Larkhall, Bath
Our Submission Status: Comment