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Upward Extension Tangles

By Roy Pinnock
January 3, 2023
  • Development
  • Permitted Development Rights
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The High Court judgment in Schneck v SoS Levelling Up, Housing & Communities (21 December 2022) illustrates some pitfalls and opportunities where two sets of Permitted Development Rights (PDR) are being explored – to convert commercial buildings to residential use and then extend them upwards.

The case concerned an office building which was in the process of being converted into 109 flats under PDR available via Class O of Part 3 of the GPDO 2015 rights when an Inspector considered the Council’s refusal of permission for an ‘upward extension’ of a further 13 homes in another storey on top of the building.  The local plan policy required affordable housing subject to viability. The authority had accepted that the financial viability appraisal (FVA) submitted with the upper extension application showed it was not viable to provide any affordable housing but nonetheless refused permission based on a breach of the policy. The Inspector’s decision to uphold this approach was, unsurprisingly, rejected as unlawful.

By the time of the appeal, the new Part 20 Class AA ‘upward extension’ PDR (new dwellinghouses on detached buildings in commercial or mixed use) was in force and was relied on by the appellant as a fallback (the Part 20 Class AA PDR). The Inspector gave limited weight to the Part 20 Class AA PDR as a fallback on the grounds that:

  • prior approval had not been given and there was no ‘certainty’ that the Part 20 Class AA PDR would therefore be available;
  • “PDRs that allow additional storeys on dwellinghouses would not be applicable to the appeal property given the conditions and limitations“.

This was rejected as unlawful:

  • applying Mansell, despite prior approval being required (and not having been granted at that stage), there was a “real prospect” of the PDR being (on the facts as explained in submissions at appeal and having regard to the lack of resistance from the LPA) available – certainty was not the appropriate benchmark and the legal error infected the exercise of planning judgement on weight;
  • the Part 20 Class AA PDR were found to be engaged on the facts.

There are limitations on the various PDR which vary and are important to bear in mind:

  • The Part 20 Class AA PDR only applies to buildings in commercial or mixed use. If the underlying office building had ceased to be commercial (because, applying the Impey doctrine, the extent of works was such that it had completed its journey to residential use), the Part 20 Class AA PDR would not apply;
  • The parallel PDR for upward extension of existing dwellinghouses (under Part 1 Class AA) is subject to a limitation that excludes its application to buildings that have become dwellinghouses by the exercise of various PDR in the first place (including Class O). In other words, if the underlying building had become residential at the point of the Inspector’s decision, by virtue of the exercise of the Class O PDR, the Part 1 Class AA PDR would not apply.

The Inspector’s decision referred to the building as being in the midst of conversion to residential use. He either decided that the use had already ceased to be commercial/ mixed (because the Class O use had come into being via the works undertaken) or simply applied the wrong test, mistaking the limits on the Part 20 Class AA PDR for those on the Part 1 Class AA PDR.

By the time the challenge came to Court, the appellant made submissions that a partial conversion to residential use had been undertaken, leaving the site in a mix of commercial and residential use. This allowed the Judge to make the finding in relation to the availability of the Part 20 Class AA PDR (albeit that it is not the fact pattern that the Inspector necessarily considered).

The outcome illustrates the sensitivity to underlying patterns of use inherent in some of the PDR.  The judgment itself also assists developers seeking to rely on the Part 20 Class AA PDR for an upward extension on a building in the process of conversion to residential – as long as part of the building is in commercial use, notwithstanding the residential conversion works, the mixed-use criteria can be met.

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Roy Pinnock

About Roy Pinnock

Roy is a partner in the Planning and Public Law team, bringing his experience of working on regeneration projects within local government and as a consultant to his legal practice.

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