23 Grosvenor Place, Lambridge, Bath
23 Grosvenor Place forms part of a monumental Grade I late 18th century terrace of townhouses situated within the Bath conservation area and World Heritage Site. The building was originally intended to be used as a hotel, but was subdivided into residential flats in the 1970s. It originally formed the initial phase of works around the proposed Vauxhall Gardens, now Kensington Meadows, by John Everleigh, and remains evidentially significant of a speculative Georgian leisure enterprise. 23 Grosvenor Place is of heightened architectural significance as it forms the aesthetic centrepiece of the terrace with a porticoed porch and grandiose Ionic columns running the full height of the principal elevation to a projecting stone balustraded parapet. The terrace has a slightly convex curve towards London Road to further centralise 23 Grosvenor Place as the visual axis of the terrace. Consequently, 23 Grosvenor Place is attributed greater significance as a designed focal point of architectural grandeur as well as wider group value as part of the terrace, indicative of speculative Georgian development and growth. As such, the terrace strongly contributes towards the Georgian Planning and Architecture OUV of the World Heritage Site.
The flats are currently undergoing renovation works for the replacement of kitchen and bathroom fittings and general redecoration works to improve the existing accommodation. It is noted that these works have been excluded from this listed building application and do not require listed building consent, as they do not constitute material alterations to historic fabric.
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 declared Climate Emergency, we appreciate the urgency of reducing energy consumption and carbon emissions, as well as upgrading our existing historic housing stock, both listed and unlisted, to meet modern standards of living and thermal performance. However, we maintain that the suitability of retrofit measures in effectively improving the energy efficiency of a building whilst sustaining the special architectural and historic interest of a listed building, and the risk of unintended consequences (eg. increased condensation, reduced breathability of historic fabric), must be assessed on a case-by-case basis.
As a council-owned building, 23 Grosvenor Place offers an exceptional opportunity to create a major case study and set the standards for the energy retrofit of a high significance Grade I building. This could establish a template for similar refurbishment works across the council’s estate, encompassing a large number of listed buildings within the city centre, and set a positive precedent to encourage similar works by private homeowners and landlords.
We therefore emphasise the need for a high quality application that appropriately considers a wide range of possible energy efficient and improvement measures in relation to the building to establish a model of best practice and ensure the optimum performance of the building in relation to its significance through the use of a ‘whole house approach’.
We have no objections to the proposed PV solar array, which would be concealed from public view within the inner roof slope. This measure would therefore have a negligible impact on the appearance of the listed building. However, considering the scale of the building and its high residential capacity (20 flats), we query whether the addition of 6 PV panels would be effective. We note the existing restrictions on available roof space due to the number of roof vents and rooflights, but strongly recommend further consideration of how PV provision could be maximised, and whether any vents could be acceptably removed or displaced to ensure that this measure would be sustainable.
In principle, BPT is supportive of the installation of secondary glazing to improve the thermal performance of the building without compromising its historic features. Secondary glazing allows the retention of historic or historic-style sash windows, and would constitute a less invasive, reversible measure with limited harm to historic fabric. We therefore feel that this measure would be a positive, easily reversible addition to improve the energy efficiency and residential comfort of a historic building and ensure its long-term, sustainable use with a low visual impact.
However, considering the scheme’s potential as a pioneering case study for council practice and guidance, we do not feel that the proposed retrofits go far enough in addressing the council’s own policies and Climate Emergency Action Plan. We maintain that the retrofit of historic buildings should ideally be approached holistically, including consideration and assessment of a wide range of possible interventions, how they would work together and any resulting impacts on the behaviour of the building or its fabric. It would be positive to include further information regarding existing measures that have already been installed at the property (eg. loft/floor/wall insulation, draughtproofing), alongside a more expansive assessment of the feasibility of other retrofit measures to work alongside the secondary glazing. In this way, a more comprehensive ‘action plan’ could be created for the building to ensure optimum performance as well as definitively ‘crossing out’ any measures which may be considered harmful to the specific architectural or historic value of the building.
In relation to the proposed amendments to the historic balustrade running from the ground to first floors, we question the practicality of welding a new handrail to the existing handrail and whether this would be suitably robust for safe usage by residents. A more structurally sound solution may be to machine screw the new handrail from underneath the existing handrail, although this would be considered a more invasive measure with resulting loss of historic fabric. Alternatively a new balustrade that sits independently behind the retained historic balustrade may be more suitable to address health and safety concerns.
As B&NES Council is making a planning application to itself, with works intended to be carried out by or on behalf of B&NES Council, we query why a Regulation 13 application has not been submitted.