Internal alterations to include construction of spiral staircase and freestanding mezzanine level, installation of lightweight internal thermal insulation to ceiling and walls, and replacement of existing front windows.
Our Response

34 Green Park Mews forms one half of a pair of Grade II early 19th century coach houses (the other being 33 Green Park Mews), situated in the Bath conservation area and World Heritage Site. The wider setting of Green Park Mews is low-rise, providing a more utilitarian frontage backing onto the Grade II late 18th century residential terrace at Green Park, with a regular Bath stone ashlar frontage, two storey height, and twin hipped roof profile across a large portion of the mews. Both 34 and 33 Green Park Mews feature blind windows across the south elevation on both the ground and first floors, with 34 Green Park Mews featuring a more unusual example of ogee window openings. Historic England notes the inclusion of 33-34 Green Park Mews on the National List “as good surviving examples of coach houses in a row of otherwise altered ones”; the retention of their historic character and appearance, including roof profile, is therefore of heightened significance due to their rarity within a mews which has otherwise undergone significant change.

BPT does not usually comment on internal changes without the benefit of a site visit. However, we note the proposed opportunity for the fitting of lightweight internal insulation.
In light of the declared Climate Emergency, BPT is generally supportive sensitive sustainability retrofits, where deemed appropriate, within the historic environment. We appreciate the urgency of reducing energy consumption and carbon production, as well as the continued, sustainable reuse of our existing building stock of which historic properties are a significant proportion.

The suitability of such changes must continue to be considered on a case-by-case basis in relation to the distinctive special architectural and historic interest of the listed building.
Whilst the use of internal insulation may be considered to be of lesser harm due to being of reduced public visibility and avoiding alterations to the external façade, we maintain that impact to internal historic fabric and any historic features or detailing of interest must be thoroughly assessed. We do not currently feel that enough information has been provided regarding the existing condition of the building or how the proposed measures would interact with historic stonework, and therefore it is difficult to appropriately assess the level of impact that works would have.

We suggest that further information is submitted regarding the proposed internal insulation, such as its thickness, finish, and how it would be secured to the Bath stone internal wall. Furthermore, from the proposed sections provided, it appears as though the proposed insulation would be limited to use across the first floor and roof space, excluding the ground floor? BPT does not have the technical expertise to offer detailed comments on the proposed insulation schematics, but we do query whether the effectiveness of the proposed measures may be limited if a whole building ‘envelope’ is not created.

This proposal, if got right, could help provide an invaluable opportunity to monitor the thermal performance of the building, before and after insulation installation, 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 internal insulation in Bath’s historic building stock.

Application Number: 21/05605/LBA
Application Date: 20/12/2021
Closing Date: 03/02/2022
Address: 34 Green Park Mews, Kingsmead, Bath
Our Submission Status: Comment