The Nest, 7 Bladud Buildings, City Centre, Bath
7 Bladud Buildings forms part of a Grade II mid-18th century terrace of townhouses situated within the Bath conservation area and World Heritage Site. It forms part of the approach to the Grade I Paragon, and cumulatively forms part of an architectural setpiece indicative of innovations in 18th century town planning utilising crescents and undulating terraces seen throughout the World Heritage Site. It forms part of a localised group of shopfronts and commercial units that broach the junction between Bath’s residential terraces to the north and north-east, and the southern approach to the city centre along Broad Street and George Street.
The focus of proposed works is at lower ground floor level, seeking to address ongoing damp issues in the under-pavement vaults. The Condition Report indicates that Cellars 1-4 have been previously cement rendered/tanked (although it is unclear as to whether these works were previously granted appropriate planning permission/listed building consent), and concrete floors have been added to Cellars 2-4, with a raised cement platform in Cellar 1. The vaults appear to be in a poor, deteriorating condition due to ongoing issues with water ingress and damp.
BPT acknowledges the difficulty of managing these poorly ventilated spaces, and we recognise that these may be susceptible to multiple forms of water ingress/damp, including run-off from the pavement above, which can be complex to address.
However, we maintain that Bath’s historic vaults and cellars are historically dark and frowsty in character and character, indicative of their typically ancillary and utilitarian function in serving the ‘host’ dwelling. Often, these are areas that have survived significant intervention or alteration, although it is evident that these vaults have been subject of substantial changes which have had a resulting adverse impact on their character and appearance, and associated contribution to the special interest of the listed building. As such, these spaces are often not suited to more ‘immediate’ habitable use where this would result in increased pressure to meet modern standards of living (eg. well-ventilated and dry) and likely necessitate further material interventions to the detriment of historic fabric and character.
We are concerned by proposals for the use of a delta membrane, to be applied over the top of existing concrete render which would be retained in situ. The existing concrete render is likely responsible for exacerbating damp conditions and water retention in the vaults by trapping moisture within the walls and will continue to have a progressive impact on the condition of the historic stonework. Whilst the applicant cites “significant damage” to the stonework as a reason against the removal of the cement, we consider that this harm should be considered against the ongoing damage to the stonework due to water retention and loss of ability to ‘breathe’, as well as harm to the historic appearance and character of the vaults themselves. The use of a membrane would further obscure the original vault walls. The photos provided also indicate areas of spalling where this would provide an opportunity for the removal of cement which is already deteriorating.
We therefore emphasise that the use of tanking should not be considered an acceptable ‘quick fix’ to address a much longer-term issue with the fabric of the building. We strongly encourage consideration of the removal of cement tanking where possible to allow the space to dry out and then re-assess what damp mitigation works may be most appropriate to balancing the historic interest and “optimum viable use” of the vaults.