20 Darlington Place, Bathwick, Bath
20 Darlington Place forms part of a terraced pair of Grade II early 19th century houses, situated within the Bath conservation area and World Heritage Site. It forms part of a wider, architecturally varied terrace of Grade II terraced houses; whilst there is some diversity in age which indicates that the terrace was extended and added to over time, it remains approximately early 19th century in date. The terrace presents a more clearly visible, yet architecturally informal, elevation along Darlington Place, with its more formalised façade orientated west to look over Sydney Buildings from an elevated position, set back within general strip plot gardens and the Grade II High Pavement. To the west, 20 Darlington Place is therefore of considerably restricted public visibility to the west, a condition which has been exacerbated by the addition of a timber pergola along the garden’s retaining wall. 20 Darlington Place has evidentially undergone significant alterations at a later date; the historic M-shaped roof profile has been interrupted with the addition of an incongruous dormer infill/extension which has subsequently impacted the historic scale and form of the building, as well as its architectural relationship with the adjoining 19 Darlington Place and the wider appearance and value of the listed terrace.
BPT is broadly supportive of the opportunity for energy efficiency retrofits where this is coherent with, and sympathetic to, the historic environment and the special interest of a listed building.
We appreciate that the existing, unsympathetic alterations to the roofscape have removed alternative PV installation options, such as within the inner roof slope, which may have been preferable and of significantly reduced public visibility.
However, BPT maintains some concerns regarding the proposed design and the absence of relevant detail from the application. We consider that the visual impact of the panels could be more significantly mitigated by pushing them further back from the roof edge, possibly to sit in line with or behind the four corner chimney stacks for an improved visual ‘containment of the panels.
We note that the application originally proposed a single flat panel, which would have offered issues with water pooling; this has subsequently been revised to incorporate multiple rows of north-south orientated angled panels. However, this has resulted in a marked increase in the perceived height of the roofline, and would be at odds with the established roof profile by introducing a series of broken ‘peaks’. The use of panels which would follow the established roof line would sit more comfortably within its setting; the use of east-west orientated panels, as previously proposed, with a slight central incline to allow for water run-off and improved energy optimisation, would retain the line whilst reducing the visual thickness of the installation.
Further, additional details are strongly recommended regarding the justification of the proposed means of fixing the panels from two steel beams. The beams serve to further elevate the panels from the existing roof surface, and consequently increase the visual height and bulk of the installation. We suggest that other options could be explored, such as directly mounting panels to the roof structure, or further details should be provided as to why this may not be viable.
There are some additional concerns as to how the proposed means of fixing the panels accounts for the potential effects of windloading on the building.
It may also be helpful to consider how the panels would be access to allow for cleaning and maintenance, to ensure that the proposed less than substantial harm is appropriately outweighed by the functionality of the panels.
We maintain that the Heritage Statement as submitted remains inadequate, and does not appropriately assess the impact of the proposed scheme proportionate to the significance of the Grade II building, or adequately describe the historic significance of the building. Whilst the principle of PV installation is positive, further details and sections are required to better understand the proposed impact to the special architectural and historic interest of a listed building, and demonstrate how the scheme has been tailored to respond to and complement the building and the wider historic character and appearance of the conservation area.