Construction of a 5m single-storey rear extension with crown roof and two roof lanterns

Appeal Decision Site visit made on 09 March 2026 by T Bennett BA(Hons) MSc MRTPI an Inspector appointed by the Secretary of State Decision date: 11 MARCH 2026 Appeal Ref: 6002736 16 Blenheim Close, Watford, Hertfordshire WD19 4QN • 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 A of the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended). • The appeal is made by Anthony Giannini against the decision of Watford Borough Council. • The application Ref is 25/01024/HPD • The development proposed is construction of a 5m single-storey rear extension with crown roof and two roof lanterns. Decision 1. The appeal is allowed and prior approval is deemed to be granted under the provisions of Article 3(1) and Schedule 2, Part 1, Class A, paragraph A.4 of the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended) for construction of a 5m single-storey rear extension with crown roof and two roof lanterns at 16 Blenheim Close, Watford, Hertfordshire WD19 4QN in accordance with the application Ref 25/01024/HPD made on 19 November 2025, and the plans submitted with it, including plan nos 1899 100, 1899 201 and 1899 203, pursuant to Article 3(1) and Schedule 2 Part 1, Class A, paragraph A.4(2). Preliminary Matters 2. Under Article 3(1) and Schedule 2, Part 1, Class A of the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended (the GPDO), planning permission is granted for the enlargement of a dwellinghouse subject to limitations and conditions. 3. Where an application is made for a determination as to whether prior approval is required for development which exceeds the limits in paragraph A.1(f) but is allowed by paragraph A.1(g) to Part 1, paragraph A.4(3) provides that the local planning authority may refuse the application where it considers that the proposed development does not comply – or that the developer has provided insufficient information to enable the authority to establish whether the proposed development complies with the conditions, limitations or restrictions that are applicable to such permitted development. 4. The description of development used in the heading has been taken from the application form. The Council’s Decision Notice uses a different description, but I have not been provided with any confirmation that this amended description has been agreed. Accordingly, I have taken the description from the original application form. Appeal Decision 6002736 2 Main Issue 5. The main issue is whether the proposed extension would be permitted under Article 3(1) and Schedule 2, Part 1, Class A of the GPDO. Reasons 6. The Council refused the application citing inconsistencies between the maximum height of the enlarged part of the dwellinghouse stated on the application form and those which the Council measured on the submitted elevation plan. Consequently, the Council considered that insufficient information had been provided to enable the authority to determine the application for prior approval as set out at A.4(2)(a), A.4(2)(b) and A.4(3)(b) of the GPDO. 7. Paragraph A.4(2)(a) of the GPDO, amongst other matters, requires a written description of the proposed development including the maximum height of the enlarged part of the dwellinghouse. At A.4(2)(b) of the GPDO, a plan showing the proposed development is required. 8. I accept there is a discrepancy between the measurements provided on the application form, which states that the maximum roof height will be 3.45 metres, and the submitted plan (drawing no: 1899 203) which indicates a height of 3.88 metres when measured to the top of the roof lanterns. While I acknowledge the appellants argument that these are secondary roof features, they nonetheless form part of the roof and therefore should have been included when calculating the maximum roof height figure. 9. Notwithstanding this, the elevation plan is an annotated, scaled drawing showing the 3.45 metre figure to the main flat roof plane of the extension. It is therefore clear how the appellant’s figure was derived. Furthermore, the Council was able to measure the drawing to establish the 3.88 metre total roof height when measured to the top of the roof lanterns. I find, therefore, that despite the measurement differences, the Council had sufficient information to establish whether the development complies with the conditions, limitations or restrictions applicable to development permitted by Class A which exceeds the limits in paragraph A.1(f) but is allowed by paragraph A.1(g) as detailed at paragraph A.4(3)(b) of the GPDO. 10. The Council have not raised any other concerns regarding compliance with other parts of the order set out at A.1(a)-(l) of the GPDO. From the submitted information I see no reason to come to an alternate view. The appeal property is semi- detached, the proposed rear extension would span the full width of the property, not extend more than 6 metres from the rear wall of the original dwellinghouse, nor would it exceed 4 metres in height. I also note that neighbouring properties were consulted and I have not been directed towards any objections from the occupiers of those properties. 11. Accordingly, based on the submitted information, I find that the proposal would comply with the conditions and limitations set out in Schedule 2, Part 1, Class A of the GPDO. Conditions 12. Paragraph A.3 of Schedule 2, Part 1, Class A of the GPDO sets out that the materials used in any exterior work must be of similar appearance to those used in Appeal Decision 6002736 3 the construction of the exterior of the existing dwellinghouse. Therefore, it is not necessary to impose an additional condition in this respect. Conclusion 13. For the reasons given above, I conclude that the appeal should be allowed and prior approval is granted. T Bennett INSPECTOR