Two-storey and single-storey extensions to existing bungalow

Appeal Decision Site visit made on 12 May 2026 by E Street BSc (Hons) MSc MRTPI Decision by John Morrison BA (Hons) MSc MRTPI an Inspector appointed by the Secretary of State Decision date: 8 June 2026 Appeal Ref: 6005787 Popes Croft, Chandlers Lane, Chandlers Cross, Hertfordshire WD3 4NE  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 Mr & Mrs Charles Webb against the decision of Three Rivers District Council.  The application Ref is 25/1648/FUL.  The development proposed is described as “two-storey and single-storey extensions to existing bungalow”. Decision 1. The appeal is dismissed. Appeal Procedure & Preliminary Matter 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. In addition, the description on the application form differs to the decision notice. However, I am satisfied that the original description whilst lacking exact specifics, is sufficient to identify the proposals at appeal. Main Issues 3. The main issues are a) whether the proposal would be inappropriate development in the Green Belt; b) the effect of the proposal on the openness of the Green Belt; and c) if the scheme would be inappropriate development, whether any harm by reason of inappropriateness, and any other harm, would be clearly outweighed by other considerations, so as to amount to the very special circumstances required to justify it. Reasons for the Recommendation Inappropriate Development 4. Policy DM2 of the Development Management Policies Local Development Document 2013 (DMP) is broadly consistent with the approach of the National Planning Policy Framework (the Framework) insofar that the development of new buildings is considered to be inappropriate, except in certain circumstances. In this instance DM2 sets out, amongst other things, that extensions to buildings that are disproportionate in size (individually or cumulatively) to the original building will not be permitted. Paragraph 154 (c) of the Framework explains that the extension or alteration of a building in the Green Belt might not be inappropriate development, provided that it does not result in disproportionate additions over and above the size of the original building. Appeal Decision 6005787 2 5. For the purposes of the Framework and DM2, the original building is as it existed on 1 July 1948 or if constructed after this date, as it was built originally. There is some additional guidance in the form Extensions to Dwellings in the Green Belt Supplementary Planning Document (SPD) which advises that a cumulative increase in floor space of more than 40% compared with the original dwelling may be disproportionate. 6. The planning history suggests that the existing building was the replacement of a timber bungalow in 1987. I have no details on the size of the original building albeit it is reasonable to assume that a more permanent masonry one would have been larger. Notwithstanding this, the existing building has grown since through a side extension and a single storey outbuilding in close proximity. 7. There is some disagreement between the main parties as to how far the situation as proposed would grow the building over the pre-existing or original size. The appellant suggests that the proposal would increase the overall net footprint by 7.29% and in terms of volume it would increase by approximately 18.9%. Whereby the Council considers that the proposed development factoring existing extensions, amounts to a 210% increase over the original floorspace and an increase of approximately 90% of the original footprint. It is important to note that the appellant’s figures are based on how this would change from the existing and not the original building. As the baseline of the original building and the scale of side extension is unknown, it is reasonable to conclude that the percentage increases would be figures somewhere between the two calculations. 8. Figures are only part of the story and neither policy nor the Framework specify an upper limit to what can represent disproportionate. The figure given within the SPD is only a guide. It is therefore a matter of judgement. The above is just a starting point. The proposal would include not only the raising of the roof, but a two-storey extension to the rear as well as the introduction of two large-pitched roof gable protrusions. It would be an accumulation of extensions which would form a significant amount of additional space outwards and upwards compared even to the existing building. It would present as a dwelling which is considerably greater than before, obscuring and subsuming the existing bungalow almost in its entirety. Whilst the visible land take would be minimal, it would create a substantially larger living space in terms of bulk and mass and together would be visually substantial. 9. Contextually speaking, and taking into account what has gone before, I can draw no other conclusion than the appeal scheme representing disproportionate additions over and above the size of the original building. In so being, the proposals would be inappropriate development in the Green Belt, contrary to the position of the Framework and Policy DM2 of the DMP. 10. The appellant has also made reference to Paragraph 154 (g) of the Framework which refers to limited infilling or the partial or complete redevelopment of previously developed land. Whether or not the appeal site could be previously developed land for the purposes of the Framework aside, the scheme would be neither limited infilling (as it is an extension expanding an existing building outward and upwards into otherwise undeveloped space) nor redevelopment. To be the latter, one would expect some form of substantive demolition and rebuilding. How far and to what extent would be a matter for judgement in each case. The appeal scheme would be development, not redevelopment. Appeal Decision 6005787 3 Openness 11. Openness is one of the key characteristics of the Green Belt. It has been held that openness has a visual and spatial aspect. The latter can be taken to mean the absence of built form. The additional height in combination with the size of the existing building, along with the additional volumes, would result in a substantial increase in height and mass. Together it would be visually prominent in its plot and thus reduce the visual aspect of the Green Belt’s openness. This is notwithstanding the immediate area’s rurality and the appeal building’s detachment from other dwellings. The existing green coverage would limit the visual effect but would not be capable of reducing its spatial effects. This would unavoidably reduce the openness of the Green Belt, contrary to the protection aims of the Framework and the DMP. This harm would be in addition to the scheme’s inappropriateness. Other Considerations 12. The Council has not identified any other harms arising from the proposal; but a lack thereof would be neutral in any case. They would carry no weight in favour of the scheme 13. There appears to be an extant prior approval under Class AA of the General Permitted Development (Order) 2015 for an upward extension to the bungalow above the main body of the house. The prior approval process does not consider Green Belt matters. 14. There is no doubt, based on the plans and the calculations provided by the appellant, that the volume and resultant floor area would be very similar to the appeal proposal. However, the schemes are not sufficiently comparable given that the prior approval scheme would be contained with the main bungalow whereby the appeal scheme would add extra bulk and sprawl upwards and outwards. A fallback is generally a scheme which could be built instead of the appeal proposal. I am not sufficiently convinced that both schemes could not be carried out in the event the appeal were to be allowed having regard to the location, configuration and design of the works in each case. Should both schemes go ahead, they would undoubtedly amount to disproportionate additions. They would result in multifaceted growth and be exponentially greater than the original building. I would therefore give only limited weight to this perceived fallback position. Conclusion and Recommendation 15. The proposal would be inappropriate development. It would also reduce its openness. Substantial weight should be given to any harm to the Green Belt. The other factors I have considered above, and as I have explained, would not be sufficient to clearly outweigh the harms I have found. Such that the very special circumstances necessary to justify the proposed development do not exist. 16. For the reasons given above the appeal scheme would not comply with the development plan and I have been given no compelling reason, taking into account other material considerations advanced, to deviate therefrom. I therefore recommend that the appeal should be dismissed. E Street APPEAL PLANNING OFFICER Appeal Decision 6005787 4 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