DEVIZES ROAD WTW, SALISBURY

Case Study

Nest Homes were asked, by the owner Wessex Water Services Limited (WWSL), to review Devizes Rd WTW, comprising of a Grade II listed Victorian Water Treatment Works (WTW) built c1850, covered Victorian reservoir, borehole and a detached house of generic 1960s design.

The challenge - securing a viable and sustainable future for the Grade II listed WTW building through conversion and development of surrounding land.

Our Heritage consultant prepared a statement of significance for the Listed building noting the important elements of the building and its curtilage, this then guided our architectural design options. Working with our architectural team, we identified the potential to demolish the existing house and replace with a terrace of three designed in a Victorian style, convert the WTW building into two dwellings and convert the reservoir for residential use.

A viability study was prepared for these options, where we recognised that to convert the reservoir would not create a suitably viable and or practical living space in its setting and that due to the abnormal costs of the WTW conversion, we would need to create additional value on site. This led us to consider replacing the reservoir with a pair of semi-detached houses replicating the design layout of the terrace, enabling the added value required to be created and ensure the preservation of the principal heritage asset.

We submitted our pre-app and following an onsite meeting with the planning officer, we were advised that the principle of residential use was acceptable but we would need to submit a heritage impact assessment identifying the level of harm to the listed building and its setting that the proposal was deemed to cause, along with a development viability report in support of our application.

Our Heritage Consultant assessed the level of harm at the lower end of less than substantial harm, due to the principal listed building (the WTW) was materially unaltered and still visibly read within the street scene. This detail was key to our planning submission, as less than substantial harm allowed us to show the benefits of the scheme, (preservation of a listed building and additional new dwellings) outweighed the harm to the setting of a listed building in accordance with the National Planning Policy Framework guidance.

We submitted our Planning Application, with supporting viability case and heritage impact assessment but our application was refused as it was perceived that substantial harm would be caused to the heritage asset, though notably no other matters of concern with the proposals were raised.

We disagreed with this outcome and appealed the decision, requesting a public hearing. At this hearing the Inspector advised that securing a continued future for the pump house was of far greater importance than retention of the reservoir and this would be guaranteed by granting planning permission and our appeal was upheld.