For the demolition of existing attached outbuilding and replacement with single storey extension. Demolition of two storey wall and replacement with glazing. Installation of patio doors

Appeal Decision Site visit made on 25 August 2026 by Andrew Fuller BSc (Hons), Dip TP, MA, MRTPI, IHBC an Inspector appointed by the Secretary of State Decision date: 25 September 2026 Appeal Ref: 6011395 Cromer Wood Cottage, Nettleden Road, Little Gaddesden, Berkhamsted, Hertfordshire HP4 1PN • 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 Dr Harry Gibson against the decision of Dacorum Borough Council. • The application Ref is 26/00160/FHA. • The development proposed is for the demolition of existing attached outbuilding and replacement with single storey extension. Demolition of two storey wall and replacement with glazing. Installation of patio doors. Decision 1. The appeal is dismissed. Preliminary Matters 2. The Council does not object to the demolition of the two storey wall and replacement with glazing or the installation of patio doors. Following the refusal of the application, these elements of the proposal were submitted separately for planning permission (ref: 26/00895/FHA) and granted. As a result, I do not need to deal with these matters as part of this appeal. 3. During the course of the appeal a revised National Planning Policy Framework (the Framework) was published. The main parties were provided with an opportunity to comment on any implications for the appeal. I have had regard to the comments and to the 2026 version of the Framework in my decision. Main Issue 4. The main issue is whether the proposed development would preserve the significance of a non-designated heritage asset and whether it would preserve or enhance the character or appearance of the Little Gaddesden Conservation Area. Reasons Heritage assets – special interest and significance Conservation Area 5. The appeal building stands within the Little Gaddesden Conservation Area (CA) where it sits along the road that runs through this linear rural settlement. The significance of the CA is in part derived from its early origins as a former agricultural settlement with a manor house and links to Ashridge Monastery and the subsequent country estate. It is characterised by a variety of architecture from Appeal Decision 6011395 2 various periods and consists of a mix of different housing. Development typically comprises low density built form on informal plots, with differing separation between buildings. 6. The Little Gaddesden Conservation Area Character Appraisal (CACA) includes mapping which illustrates groups of buildings along the length of the village. This shows the close relationship of the appeal site with its neighbours at Cromer Cottage and Nos 1-8 Ashridge Cottages, which form a slightly denser group of built form. Many buildings and outbuildings are set back from the street, in some cases largely out of public view. Hedging and trees are extensive and frequently enclose sites offering varying degrees of screening. The appeal site is typical of many buildings in the CA in its relationship with the public realm. It extends away from the road with some significant screening. Nonetheless, the spaces around it, its historical importance and development as a modest workers cottage, are characteristic of, and contribute positively to, the setting of the CA as a whole, and therefore to its significance. Non-designated heritage asset 7. The appeal site is identified as a non-designated heritage asset (NDHA). Within the CACA it is described as once being two estate workers cottages dating back as early as the 17th century, with 18th, 19th and 20th century additions. It has also been significantly extended during this century and now comprises a mix of materials, including render, painted brickwork, elements of timber framing, wattle and daub, and both a clay tile and slate roofs. Its principal two-storey range extends away from the road, with a secondary wing at 90 degrees parallel to the road. 8. Attached to the far end of the main range is a narrow, single-storey former stable wing, now converted to residential accommodation. This part of the building dates broadly to the early 19th century and slopes down and away from the principal house, following the fall in ground level of the garden. 9. The Design, Access and Heritage Statement identifies only the walls of the former stable wing to be original fabric. On my site visit I saw the alterations both internally and externally to the roof, windows and other components of this structure. Considering its age and the retention of its overall form, these adaptions do not reduce the contribution the former stable wing makes to the overall significance of the site. 10. As well as its aesthetic value, the significance of the cottage comprises the survival of early fabric. This includes its plan form, along with areas of early ancillary function, such as the stable wing, which together are key aspects of the building’s overall significance as a NDHA and contribute positively to its significance. Heritage assets – appeal proposal and effects Conservation Area 11. The proposal would remove the former stable wing and replace it with a single- storey extension to the rear, finished in painted brickwork, timber cladding and patinated copper. The appellant has suggested that the proposed extension would not be significantly larger than the existing stable wing and would be of a Appeal Decision 6011395 3 commensurate height to it, therefore making it subservient. Be that as it may, I note that the extension would still be wider than the plan form of the original main range of the cottage, which would therefore not be subordinate. 12. Alongside the loss of the former stable building, by reason of the deep plinth sat above the sloping garden, the replacement structure would appear more dominant than the existing former stable wing to the rear of the building. The resulting composition, in conjunction with the other various extensions since 2000, would excessively enclose and alter the modest historic phasing of the original cottage (identified in the CACA). As such the proposal and these other modern additions would cumulatively dwarf its earlier form and thereby harm the wider character and appearance of the CA. 13. The existing stable wing is not easily glimpsed from the street scene, in the same way that the proposal would be difficult to be viewed from the road or other public aspects. However, this is the case for many aspects of the various buildings and heritage assets that together make up the CA and contribute to its significance. 14. On my site visit, as highlighted by the appellant, I saw other houses in the CA that had gained planning permission for extensions. This includes an extension at Manor Cottage, the planning permission of which is provided in evidence. In respect of this, the properties are of different sizes and forms, as are the extensions, and therefore it is not directly comparable to the appeal site and proposal. 15. My attention has been drawn to the CACA which notes that the CA has successfully accommodated a variety of successive architectural styles and building materials. However, the appeal site already displays a variety of timber, brick, tile and render in various forms and the introduction of further materials, such as the metal cladding, would be incongruous. 16. For the reasons outlined above, I conclude that the proposed development would fail to preserve or enhance the character or appearance of the Little Gaddesden Conservation Area, contrary to the requirements of section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act). Non-designated heritage asset 17. The appellant asserts its poor construction and the presence of cracking within the masonry to the former stable building. During my site visit I saw some very localised areas of cracking. However, in the absence of a structural-building survey undertaken by a suitably qualified conservation accredited expert, there is no substantive evidence to support the loss of this part of the building. Whilst poor insulation, cold and damp are also stated in evidence to be further reasons for the demolition of the structure, these are issues facing many historic buildings and does not in itself justify demolition in this instance. 18. Whilst distinctly modern, the proposed extension departs from any design references within the existing building. Its width is such that it would not reflect the hierarchy of a subordinate addition, and its roof pitch is at odds with the steeper pitches of the various existing roofs across the property. 19. In making my decision, I have had regard to Appendix 7 of the Dacorum Borough Local Plan 1991-2011 (2004) (Local Plan). It requires, amongst other things, for Appeal Decision 6011395 4 the outward projection of rear extensions to have regard to the visual effect of the extension on the original building and the retention of space around it. I find the extension proposed would be deeper and therefore more prominent than the existing structure. When taken together with other more recent extension implemented, the NDHA would no longer be the prominent component of the overall composition. Therefore, for the reasons outlined above, I conclude that the proposed development would fail to preserve the significance of this non- designated heritage asset. Heritage assets – public benefits and balance 20. Policy HE6 of the Framework advises that when considering the potential effect of a development proposal on the significance of a designated heritage asset, substantial weight should be given to the asset’s conservation. It goes on to state that any harm to a designated heritage asset will be a matter of considerable importance and weight. Given my findings above, and the extent of the proposed development, I find harm which is of considerable importance and weight. 21. Under such circumstances where harm is caused, Policy HE6 advises that the effect on the asset and its significance should be weighed against any public benefits resulting from the proposal. In the case of the NDHA, Policy HE7 directs that where development proposals would harm the significance of a non- designated heritage asset, that this should be weighed against the benefits of the proposal and a balanced judgment made, having regard to the scale of any harm and the significance of the non-designated heritage asset. 22. I acknowledge that there would be some energy efficiencies as a result of the new extension. However, details of the performance of the existing building, the challenges relating to modifications, as well as the performance of the proposed building are not put to me in detailed evidence. Nevertheless, due to the limited scale of the proposed development this would be modest. Moreover, the continued viable use of the appeal property as a residential dwelling and replacement low- quality brickwork, is not dependent on the proposal as the building has an ongoing residential use that would not cease in its absence. While I have had regard to the proposal providing a widened usable floor space, this would be a private benefit for its occupiers. 23. I therefore conclude that the weight that I ascribe to the public benefits from the proposal, is not sufficient to outweigh the importance and weight that I attach to the harm I have found to the heritage assets. Accordingly, I conclude that the proposed development would fail to preserve or enhance the character or appearance of the CA. The proposal would also cause harm to the significance of a NDHA. The proposed development would be contrary to the requirements of section 72(1) of the Act and Policy CS27 of the Dacorum Borough Council Core Strategy 2006-2031 (2013) (Core Strategy). This policy states that all development will favour the conservation of heritage assets and requires, amongst other matters, for development to positively conserve and enhance the appearance and character of conservation areas. Other Matters 24. The site lies within the Chilterns National Landscape (CNL) where there is a statutory duty on decision-makers to seek to further the purpose of designation. Appeal Decision 6011395 5 The primary purpose in respect of the CNL is to conserve and enhance the natural beauty of the designated area. 25. The site contributes positively to the CNL through its overall form, the use of traditional materials and grouping with other buildings within the landscape. The site also contains numerous mature trees and landscaping which positively contributes to the verdant, rural character within the immediate surrounding area and the qualities of the NL. The extension would be positioned within the rear garden and surrounded by trees. Nonetheless, by reason of its relatively limited scale and its contained position in relation to open aspects within the CNL, the proposed development would conserve the natural beauty of the CNL. 26. The site is located immediately adjacent to Nos 1-8 Ashridge Cottages, a grade II listed group of buildings 1(LB). The setting of listed buildings do not form part of the Council’s reason for refusing the proposed development. Nonetheless, in line with section 66(1) of the Act, I have paid special attention to the desirability of preserving the setting of these LBs. 27. Nos 1-8 Ashridge Cottages date to 1928-29 and comprise a range of two-storey properties finished in render and roofed in pantiles. Their significance is aesthetic and historic and relate to their ordered form as estate housing designed by the renowned British architect Clough Williams-Ellis. Their setting is typical in relation to a linear village, with the cottages running along the street and set back behind modest gardens, despite the entrance to No 1 facing sideways towards the appeal site. The position of the group forwards of the appeal property, along with significant boundary treatment, screens most of the proposed development from these LBs. As such, the proposal would not harm the significance of these LBs. Nevertheless, the lack of harm in this respect does not weigh for or against the appeal and does not alter my conclusions on the main issue. 28. I understand the wishes of the appellant to provide more functional accommodation in terms of layout, usability and energy efficiency and reduce heating costs. However, I do not consider that additional, flexible, modern living accommodation to the rear of the property provide sufficient justification to outweigh the harm I have identified from the proposal. 29. The appellant sets out that the scheme would meet other planning objectives, including in respect of principle, impact on the countryside, highways, living conditions and effect on protected species. However, a lack of harm is effectively neutral in my determination of the appeal. Furthermore, by positioning the proposed development further away from the boundary with neighbouring occupants at Cromer Cottage than the existing former stable building, the appellant asserts that the proposed development would improve neighbouring living conditions. However, as the former stable block is longstanding on the site, its relationship with this neighbour cannot be contested and as such this carries little weight in favour of the proposal. 30. The absence of the appeal building as a local listed building in the Hertfordshire Historic Environment Record does not lessen its significance as a NDHA. Similarly, the lack of a Management Strategy within the CACA does not prejudice decisions for proposals within the CA which must still be made against the development plan, the Framework and the Act. 1 Listed Building Entry Number: 1389396 Appeal Decision 6011395 6 Conclusion 31. For the reasons given above, I conclude that the appeal proposal would conflict with the development plan when read as a whole. There are no material considerations, including the Framework, that indicate that the development should be determined other than in accordance with it. Therefore, the appeal is dismissed. Andrew Fuller INSPECTOR