Appeal 3344478

The appeal is dismissed.

The Places for Everyone Joint Development Plan (PfE) was adopted by nine [name] authorities, including Rochdale Metropolitan Borough Council, in March 2024. It replaces some policies, or sections of policy, of the adopted [name] (2016) (CS). Both parties have had the opportunity to comment on the PfE and the Council have confirmed that [name]-P1 and JP-P2 should be read alongside those policies of the CS referred to in the decision notice.

The main issues in this case are i) the effect of the proposed single-storey front extension on the character and appearance of the host dwelling, a non-designated heritage asset; and ii) whether sufficient evidence is available to demonstrate that the proposed front extension would not result in instability of the adjoining canal embankment.

The appeal property is a c. [postcode] former lockkeepers cottage (the Lockhouse), located adjacent to [name] 48 of the [name]. The Lockhouse is two-storeys, with three-storeys to the rear as the land falls steeply to [name] and rows of mid [postcode] terraces along [address] and [address]. It has a ‘T-shaped’ plan form, relatively narrow in depth, with a projecting gable feature facing the canal. The Lockhouse is set behind a small front garden, is constructed in stone on the ground floor with mock Tudor timber framing at first floor and has a modern conservatory extension off the front elevation (north-east corner).

It is proposed to demolish the existing conservatory and construct a single-storey extension across more than the full width of the front of the Lockhouse, projecting a maximum 3.6m from the principal (lock side) elevation, and 1.22m forward of the projecting gable. The proposed front extension would also project around 3m to the side, wrapping around the flank (south-west) elevation up to the existing boundary retaining wall.

The Lockhouse has been identified by the Council as a non-designated heritage asset. This is not disputed by the appellant, although it is argued that the weight given to this should be moderate because the Lockhouse is not identified on the Council’s published list of non-designated heritage assets. The significance of the Lockhouse is derived partly from its historic association with the first phase of construction of the Rochdale canal, and its group value with Lock 48 and [name], but also its architectural merit.

In this regard, the appellant has drawn my attention to an appeal decision for the demolition of an existing building and erection of a residential block of flats at [address] in Crewe (APP/R0660/W/23/3316272) argued to be relevant to this case. Save a copy of the appeal decision, I have been provided with no further information or drawings in respect of that proposal to establish whether, or not, it is comparable to the appeal proposal before me. I note, however, the opinion of the Inspector at paragraph 16 (to which the appellant refers me) that ‘whilst the building retains some of its original features there have been several alterations and additions that significantly compromise its architectural merit, and as such it does not have any features that merit significant architectural or historic value.’ I do not share a similar opinion in respect of the Lockhouse.

There have clearly been alterations to the fenestration of the Lockhouse, notably the replacement of multi-pane timber sash windows with uPVC windows and replacement of the lean-to porch to the right of the projecting gable with the modern conservatory. I also recognise that historic mapping shows extensions at either end of the Lockhouse that have been removed. However, the original narrow, ‘T-shaped’ plan form and characteristic gable, set back from the tow path, remain legible as do architectural features on the front elevation including the ground floor stonework, stone corbels, jettied first floor and supporting piers. The siting, form and architectural features of the Lockhouse contribute to its significance and its relationship and composition with the adjacent lock and canal.

The proposed extension has been designed with a flat roof and gabled front porch which would be sited centrally within the original elevation of the Lockhouse. I acknowledge that the height of the proposed extension is modest and that the guidance in the Council’s Guidelines and Standards for Residential Developments Supplementary Planning Document (2016) (SPD) does not explicitly refer to the acceptability (or otherwise) of a flat roof design. However, the scale of the proposed extension – which would be 3m wider than the original front elevation and would project forward of the facing gable – would fail to appear as a modest intervention. I note that additional glazing would be introduced, with full height glazed doors and a glass balustrade at first floor, and new windows at ground floor. However, because of its scale, siting to the front and stone construction, rather than having a ‘lightweight appearance’ as suggested by the appellant, I find it would appear a non-subservient addition that would dominate its host. It would therefore conflict with the SPD guidance that house extensions should be designed to be in keeping with the host property and generally subservient to it.

I accept that the existing conservatory does not particularly contribute to the character and appearance of the Lockhouse, but, rather than contributing to a jumbled appearance of the front elevation, I observed it to be a small, discreet and predominantly glazed addition which allows for the form and plan of the Lockhouse to be read and understood. In contrast, the proposed extension would entirely alter the form of the Lockhouse and would mask some of the original features, such as the jettied first floor and supporting piers, which contribute to its significance as a non-designated heritage asset.

For these reasons, I conclude on the first main issue that the proposed single-storey front extension would cause less than substantial harm to the significance of the host Lockhouse, a non-designated heritage asset. Paragraph 209 of the National Planning Policy Framework (the Framework) requires that, in weighing applications that directly or indirectly affect non-designated heritage assets, a balanced judgement is carried out, having regard to the scale of any harm or loss and the significance of the heritage asset.

The appellant has advanced benefits associated with the proposal, notably the effective use of land and job opportunities created during the construction of the extension. I also recognise that the proposed extension would provide valuable additional ground floor living accommodation for the appellant’s family, including a study and larger kitchen and dining area. [name] accept these are benefits of the proposal, I find them modest and not sufficient in this case to outweigh the less than substantial harm I find to the significance of the Lockhouse.

Consequently, in addition to a conflict with the guidance in the Framework, the proposed front extension would conflict with [name] DM1 and P3 and PfE Policy JP-P1 which together require development proposals to be of high quality design, and take the opportunity to enhance the quality of the area, its identity and sense of place, by respecting context and character in terms of design, siting, size and scale. It would further conflict with CS Policy P2 and PfE Policy JP-P2 in so far as they require development to protect and enhance character, conserving, enhancing and promoting key heritage assets, both statutory and non-statutory.

The existing Lockhouse is built into the side of the canal embankment structure and the consultation response from the Canals & Rivers Trust (C&RT) advises that the canalised wall of the Lockhouse and the wider embankment support the canal above land to the north. In the absence of supporting details in the form of foundation details and calculations by an apparently qualified person, concern is raised by the C&RT and Council in respect of the additional loading resulting from the proposals and the potential risk of collapse of the embankment.

CS Policy G9 requires that any risks arising from contaminated land or land instability, and appropriate actions to address these risks, are identified prior to any development taking place on that land and the identified actions taken. The guidance at paragraph 189 of the Framework is also that planning decisions should ensure that a site is suitable for its proposed use taking account of any risks arising from land stability. Further guidance in the Planning Practice Guidance (PPG) is that a preliminary assessment of ground instability should be carried out at the earliest possible stage and that applicants should ensure that any necessary investigations are undertaken to ascertain their site will remain stable, or can be made so as part of the development.

The appellant’s case is that, following the land stability flowchart in the PPG, which details steps a planning authority should follow, this matter could have been adequately conditioned, requiring the submission of a land stability report, foundation details and supporting calculations for the canal embankment retaining wall. However, the flowchart is predicated on the basis that, as a minimum, a preliminary assessment of the site, including desk-top study and site visit is carried out, which identifies risks of land and/or slope stability, and whether these are acceptable, or can be mitigated to an acceptable level.

I recognise that the appellant offered to submit a stability report during the course of determination of the planning application, but in the absence of even a preliminary assessment it is not possible to ascertain the potential stability risk in this case, or whether that risk could be mitigated. I therefore conclude that the proposal conflicts with the guidance in the Framework, as well as CS Policy G9.

For the reasons given above, I conclude that the appeal should be dismissed.