40 Park Street, Lansdown, Bath
40 Park Street is a Grade II late 18th century terraced townhouse, situated within the Bath conservation area and World Heritage Site. It forms part of a high concentration area of listed buildings, included the individually-listed Grade II dwellings along Park Street, the individually-listed Grade I dwellings at Cavendish Place, and the adjoining, group-listed Grade I late 18th century ensemble at St James’s Square. 40 Park Street forms part of a key connector between St James’s Place and other architectural ensembles integral to Bath’s Outstanding Universal Values such as Lansdown Crescent and Cavendish Crescent via Cavendish Road. As such, 40 Park Street is attributed cumulative group value as an indicative element of Georgian town planning, material form, and grain. It has further evidential significance as part of the unfinished St James’s Square development, now truncated at the four shortened streets that intersect with the central Square.
We suggest further details such as the means of fixing the proposed glazed screen within the jack arch would better clarify the material impact of the scheme. It is recommended that fixings are limited to mortar joints, or any instances of pre-existing fixing points to limit harm to historic stonework.
BPT recognises the issues highlighted as part of this application, such as the ongoing damp issues in the northern vault exacerbated by a leaking surface water pipe. This has been reported to have led to the deterioration and loss of fabric such as historic lime render. We are therefore supportive of remediation measures to address ongoing harm to the listed building, such as the proposed reconnecting of the pipe to the drain to redirect surface waste. We additionally welcome the opportunity to improve the passive ventilation of the vaults to address ongoing damp issues with limited intervention.
However, we have some concerns regarding the proposed conversion of the front half of the northern vaults into an additional lower ground floor bathroom. We continue to reiterate the unsuitability of vaults for directly residential use due to naturally damp conditions and poor air quality, with vaults being better suited to ancillary facilities or storage space instead. The use of vaults for a directly domestic function, such as a bathroom, would not be suitable, either for the comfort of human usage or the alteration of historic fabric to meet modern standards of utility. The intensification of direct use of the space by residents as well as an associated increase in temperature and humidity would place increased pressure on further intrusive waterproofing and damp mitigation works in future.
It is as yet unclear as to why a bathroom conversion is proposed when bathroom facilities are already present at lower ground floor level.
The proposed installation of tanking (“Delta tanking system”) on the internal dividing wall of the proposed bathroom would be a more visually and materially intrusive measure which would entirely obscure the historic stone finish of the vaults’ interior. This is not comparable to either the proposed limewash treatment, or the existing remnants of lime mortar, where this allows for the underlying stonework to remain materially legible. Furthermore, the justification of works is unclear; the D&A Statement highlights that “a Delta waterproofing system is proposed to be used sparingly, only in the areas where surface water/damp are an issue beyond an acceptable level, and to protect the long-term integrity of the vaults’ structure.” However, dealing with the source of the damp issue (ie. the leaking pipe) should appropriately mitigate against excessive damp ingress (beyond what is typical for Bath’s traditional vaults and cellars) without the need for further intervention.
Should further treatment be required, we strongly recommend that the use of a traditional solution such as a limewash should be implemented which would be more sympathetic to the material qualities and character and appearance of the vaults.