For a single storey rear extension and erection of rear box dormer

Appeal Decision Site visit made on 18 August 2026 by Andrew Fuller BSc (Hons), Dip TP, MA, MRTPI, IHBC an Inspector appointed by the Secretary of State Decision date: 04 September 2026 Appeal Ref: 6012069 20 Pitbank Drive, Collingtree, Northampton NN4 0AQ • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a refusal to grant planning permission. • The appeal is made by Harpreet Kaur against the decision of West Northamptonshire Council. • The application Ref is 2026/1791/FULL. • The development proposed is for a single storey rear extension and erection of rear box dormer. Decision 1. The appeal is dismissed insofar as it relates to the erection of a rear box dormer. The appeal is allowed insofar as it relates to the single storey rear extension at 20 Pitbank Drive, Collingtree, Northampton NN4 0AQ in accordance with the terms of the application Ref 2026/1791/FULL, subject to the following conditions: 1) The development hereby permitted shall begin not later than 3 years from the date of this decision. 2) The development hereby permitted shall be carried out in accordance with the following approved plans: AD-OS (OS Map) and AD-01-01 (Proposed Drawings) except in respect of the rear box dormer. 3) The external materials of the extension hereby permitted shall match those used in the existing dwelling. Preliminary Matters 2. The reason for refusal cites the addition of rooflights. Within the Delegated Report these are described as ‘three front rooflights’. The only rooflights present on the submitted plans are positioned within the roof of the proposed single storey rear extension. As the Council considers the single storey extension to be acceptable, I have considered them with that part of the proposal and therefore made my decision on that basis. 3. A new emerging local plan for the whole of West Northamptonshire was published for consultation between 8 April and 2 June 2024. The local plan is still in the early stages of preparation, whilst its policies are a material consideration, I afford them limited weight at this stage. 4. A revised version of the National Planning Policy Framework (the Framework) was published on 17 August 2026. The changes to the Framework do not affect the merits of this case in a material way and I, therefore, have not consulted the parties with regard to these changes. Appeal Decision 6012069 2 Main Issue 5. The Council’s reason for refusal relates to the rear box dormer and the roof lights only and it is clear from its submissions that the Council does not have any concerns about the single storey rear extension. I have no reason to disagree with those findings. On this basis, the main issue is the effect of the proposed rear box dormer and the rooflights on the character and appearance of the property and surrounding area. Reasons 6. The appeal site is situated within a modern housing estate where properties predominantly have gabled roofs pitched at various angles. A limited number of houses have within their roof slopes, either gable features over half-storey attic room windows or small flat or gabled dormer windows. 7. The appeal site occupies a corner plot, with Churchfield Way to the side. As such, neighbouring properties in this street are positioned to the rear of the appeal property. Moreover, they are set back sufficiently from the street so as to allow a relatively clear view of the rear first floor and roof form of the appeal site along Churchfield Way. 8. The proposed development seeks to introduce a dormer structure across a significant portion of the rear roof slope of the appeal property. This would be sat close to the eaves and side gables and set only slightly down from the ridge where a flat roof would be formed over it. The proposed development would be highly visible in Churchfield Way, in particular along the approach from Watermill Way. Its proportions, along with its extensive flat roof, would not reduce its visual prominence and it would be uncharacteristic when seen in conjunction with the established pitched roofs across the surrounding area. 9. In making my decision, I have had regard to the Council’s Residential Extensions and Alterations Design Guide: Supplementary Planning Document (2011) (Design Guide SPD). It requires dormers to be proportionate to the roof so as not to be dominant, incorporate a pitched roof, and reflect the window design of others in the building. Despite being set down from the ridge and set in from the side elevations the dormer is not subordinate or modest in scale. 10. On my site visit, and as highlighted by the appellant, I saw that a number of nearby houses have dormers, including at No 133 and 135 Watermill Way. However, the design and scale of these dormers is such that they generally respect the characteristic roof form of properties by being subordinate to the roof slope in which they sit. This is in marked contrast with the appeal proposal. Ultimately, the existence of those other dormers across the estate has not led me to an alternative conclusion on this main issue. 11. I note that the estate is relatively new and as such no new roof dormers were evident to me on my site visit. Nevertheless, the absence of other rear dormers in the area weighs neither for nor against the appeal scheme. 12. As I have already found that the proposed rooflights form part of the single storey extension and as I am dismissing the proposed dormer, in my judgement the rooflights would not cause visual clutter. Appeal Decision 6012069 3 13. Overall, although I find the single storey rear extension and roof lights to be acceptable, I conclude that the proposed rear box dormer would harm the character and appearance of the property and surrounding area. As such, it conflicts with Policy S10 of the West Northamptonshire Joint Core Strategy Local Plan (Part 1) (2014), and Policy Q1 of the Northampton Local Plan Part 2 2011- 2029 (2023). Together these policies, amongst other things, seek development to contribute to good placemaking through high quality, beautiful and sustainable design which encourages the creation of a strong, locally distinctive sense of place. Other Matters 14. I understand the wishes of the appellant to respond to their changing needs at the property. However, I consider that the additional living accommodation in the roof space would not provide sufficient justification to outweigh the harm I have identified from the proposal. 15. The reasons pertaining to the removal of permitted development rights across the estate are not before me in evidence. Accordingly, the proposed development must be assessed having regard to the current circumstances of the site and its surroundings and considered on its own planning merits. 16. For the reasons set out above, I have found harm in relation to the rear box dormer. However, the proposed single storey rear extension is clearly severable from the rear box dormer extension being both physically and functionally independent. Therefore, in this case, under section 79(1)(b) of the Town and Country Planning Act 1990, I am able to issue a split decision and grant planning permission for the rear extension. This is how I shall proceed. Conditions 17. The Council has suggested a set of conditions in the event that the appeal is allowed. In imposing conditions, I have had regard to the tests within the Framework, the Planning Practice Guidance, and the relevant statutes. 18. In addition to the standard time condition (1), I have imposed a condition identifying the relevant drawings to provide certainty, although I have also clarified that the approval of plans only relate to the single storey rear extension (2). Finally, a condition requiring materials to match those used on the existing house to maintain the character and appearance of the local area is imposed (3). Conclusion 19. For the reasons given above, I conclude that the appeal should be allowed, subject to the conditions listed, insofar as it relates to the single storey rear extension but dismissed insofar as it relates to the rear box dormer. Andrew Fuller INSPECTOR