Construction of vertical extension to create additional storey

Appeal Decision Site visit made on 30 March 2026 by S Manson DipTP MRTPI Decision by John Morrison BA (Hons) MSc MRTPI an Inspector appointed by the Secretary of State Decision date: 22nd April 2026 Appeal Ref: 6004117 The Summerhouse, Guilden Sutton Lane, Guilden Sutton CH3 7EX • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a refusal to grant approval required under Article 3(1) and Schedule 2, Part 1, Class AA of the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended). • The appeal is made by Peter Hawkins against the decision of Cheshire West and Chester Council. • The application Ref is 25/03105/PAA. • The development proposed is the construction of vertical extension to create additional storey. Decision 1. The appeal is dismissed. Appeal Procedure 2. The site visit was undertaken by a representative of the Inspector whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal. Preliminary Matter 3. Article 3(1) and Schedule 2, Part 1, Class AA of the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended (GPDO), permits development consisting of the enlargement of a dwellinghouse by the construction of one additional storey, where the existing dwellinghouse consists of one storey, together with any reasonably necessary engineering operations. In the event development is permitted under AA.(b) this is subject to limitations and conditions set out in Paragraphs AA.1 and AA.2. Main Issues 4. The main issues are a) whether or not the proposed development would accord with the limitations of Class AA with specific regard to the principal part of the dwelling; and b) the effect of the proposal on the external appearance of the dwellinghouse. Reasons for the Recommendation Limitations of Class AA 5. The appeal property is a detached, single storey timber building of elongated, linear form. It was formerly a small outbuilding with a low mono‑pitched roof that has since been incrementally extended either side by substantial flat-roofed additions, finished in horizontal timber cladding. These elements together give the building a Appeal Decision 6004117 2 low overall height and a utilitarian appearance. The site has open rural areas to the north and west with neighbouring development to the south, and an access lane along the east. 6. Class AA development is not permitted where any additional storey would be constructed other than on the principal part of the existing dwellinghouse, as required by Paragraph AA.1(i) of Schedule 2, Part 1 of the GPDO. The GPDO gives a specific definition of “principal part” for the purposes of this Class, which is the main part of the dwellinghouse, excluding any front, side or rear extension of a lower height, regardless of whether such extensions form part of the original dwellinghouse or were added subsequently. 7. The proposal seeks to construct an additional storey across the full width and depth of the building, including over the flat‑roofed side additions. However, these side elements are clearly lower in height than the central section and therefore fall within the category of extensions expressly excluded from the “principal part”. Development above them cannot therefore be regarded as development on the principal part of the dwellinghouse. 8. Furthermore, there is a recessed section on the rear elevation, creating a clear indentation in the building’s footprint. The submitted plans do not depict this indentation and instead show a squared‑off form, which does not reflect the dwelling as it actually exists on site. By presenting a simplified, regularised footprint, the drawings depict the proposed additional storey as extending over areas that are not currently part of the principal part of the dwellinghouse. As a result, the works shown would not be constructed solely above the main part of the dwellinghouse but would extend onto excluded and non-existing, lower sections. Accordingly, the proposal fails to satisfy the concerned limitation in AA.1(i). 9. The intention of Class AA is to allow an additional storey to be added only to the main, existing structure of the dwellinghouse. In this case, the squaring‑off of the footprint and the extension of built form over the lower side additions both serve to take the development beyond the established principal part. These elements amount to development on parts of the building that cannot be treated as the principal part and therefore would not accord with paragraph AA.1(i). External Appearance 10. Even if the development had met the requirements of Schedule 2, Part 1, Class AA in all other respects, Condition AA.2.(3)(a)(ii) requires consideration of the external appearance of the dwellinghouse, including the design and architectural features of the principal elevation of the dwellinghouse. 11. The use of extensive timber boarding at first‑floor level would introduce a material and finish that is not characteristic of the surrounding brick‑built and rendered dwellings and would appear visually discordant within the surrounding area. The resulting dwelling would be boxy and incongruous when viewed alongside the predominantly traditional built form, and while weatherboarding exists elsewhere in the wider area, it is used only as a secondary, decorative feature rather than in such a dominant and expansive manner. 12. Thus, the proposed development would have an adverse effect on the external appearance of the dwellinghouse, contrary to the design principles set out in the Framework. It would accordingly fail an assessment under the above condition. Appeal Decision 6004117 3 Other Matters 13. Appeal 3293165 refers to an existing two‑storey brick‑built dwelling of a markedly different scale, form and architectural context. In that case, the Inspector noted that although the proposal involved a lower ridge, this was an intentional and coherent design feature. It therefore does not provide a meaningful point of comparison with the appeal scheme before me, which relates to a low‑lying, elongated timber structure. The proposed additional storey would extend across the full width and length of the building, rather than forming a subordinate or articulated design response. 14. Accordingly, the circumstances and reasoning in that appeal are materially different and attract little weight in my consideration of the current proposal. In any case, a decision under the permitted development regime would not generally have regard to other material considerations in the same way as one where express planning permission is sought. 15. Views of the site maybe restricted, however, limited visibility does not outweigh the failure to comply with the limitations of Class AA or the harm identified to the external appearance of the dwellinghouse. The lack of objection from neighbouring occupiers is noted, but this is a neutral matter and does not indicate that the proposal satisfies the relevant prior approval criteria. Putting aside the preceding paragraph. Conclusion and Recommendation 16. For the reasons given above, the appeal scheme would fail to accord with specific limitations and conditions of the above mentioned permitted development class. It would thus neither satisfy the definition of permitted development set out thereby and would fail an assessment under prior approval. I therefore recommend that the appeal should be dismissed. S Manson APPEAL PLANNING OFFICER Inspector’s Decision 17. I have considered all the submitted evidence and my representative’s report and on that basis the appeal is dismissed. John Morrison INSPECTOR