Outbuilding conversion to apartments and roof replacement from thatched roof to tiled roof

Appeal Decision Site visit made on 13 and 14 January 2026 by M J Francis BA (Hons) MA MSc MClfA an Inspector appointed by the Secretary of State Decision date: 9 February 2026 Appeal Ref: APP/J0540/D/25/3373080 4 Werrington Mews, Werrington, Peterborough PE4 6GJ • 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 Mrs Margherita Chiarizia against the decision of Peterborough City Council. • The application Ref is 25/00408/HHFUL. • The development proposed is outbuilding conversion to apartments and roof replacement from thatched roof to tiled roof. Decision 1. The appeal is dismissed. Preliminary Matters 2. The description in the banner heading, which is from the application form, refers to the conversion of the building to apartments. During the determination of the application, the proposal was amended to an annex, however, the Council did not refuse it on this basis. As I was unable to access the building, I have not seen whether the conversion shown on the proposed floor plan is appropriate. 3. The proposal has been refused in part because it affects the setting of a listed building and it is within a conservation area. As required by sections 66(1) and 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act), I have had special regard to the desirability of preserving the building or its setting or any features of special architectural or historic interest which it possesses; and paid special attention to the desirability of preserving or enhancing the character or appearance of the conservation area. Main Issues 4. The main issues are the effect of the proposal on: • the significance of the outbuilding, a non-designated heritage asset (NDHA); • the setting of the grade II listed building, No 123 Church Street; and • the character or appearance of the Werrington Conservation Area (CA). Reasons The NDHA 5. The appeal site is located within the back garden of No 4 Werrington Mews (No 4) where it forms the rear and part of the side boundary wall of the property. No 4 is a Appeal Decision APP/J0540/D/25/3373080 2 detached, two-storey dwelling, at the entrance to a small cul-de-sac of houses within the centre of the CA. 6. The single storey outbuilding is constructed of a rubble stone with a thatched roof. It has modern windows on the southeast elevation, overlooking the garden, and southwest elevation facing the adjoining driveway. The thatch is in poor condition, with moss growing on it and a tarpaulin covering some of the roof, having partly blown off at the time of my visit. 7. The appellant seeks to replace the thatch with a tiled roof. They consider that the cost of replacement of the thatch is disproportionate given the scale and limited heritage significance of the structure, although acknowledge that the building contributes to the traditional character of the area. 8. The Council reference that the building is shown on a 19th century map, although acknowledge that the building may pre-date this. They consider that it is a NDHA with aesthetic and historic heritage value and significance. 9. The Planning Practice Guidance (PPG) indicates that non-designated heritage assets (NDHAs) are buildings, monuments, sites, places, areas or landscapes identified by plan-making bodies as having a degree of heritage significance meriting consideration in planning decisions, but which do not meet the criteria for designated heritage assets. 10. The location of the building within a domestic garden and amongst a modern group of houses has altered how the building is now experienced. However, it is of historic interest, and its significance derives from it being an example of a simple building which would have been commonly found in a village where in previous centuries, agriculture was the main occupation. Moreover, its construction in stone, with a thatched roof, points to the widely available local materials that were formerly used in buildings; thatch being a characteristic and important roofing material in the Fens. 11. Paragraph 216 of the Framework indicates that the effect of an application on the significance of a non-designated heritage asset should be taken into account in determining the application. In weighing applications that directly or indirectly affect non-designated heritage assets, a balanced judgment will be required having regard to the scale of any harm or loss and the significance of the heritage asset. 12. Policy LP19 of the Peterborough Local Plan 2016 to 2036, 2019, (PLP), recognises the protection of significant non-designated heritage assets and their settings, including a presumption in favour of their retention, and any special features which contribute to an asset’s significance should be retained and reinstated, where possible. 13. The appellant refers to water leaking into the building over a long period which has led to structural issues, including cracks in internal and external walls. The Council contend that the building has not been properly maintained. From what I saw, the building has been in a poor state of repair for some time, but I have no evidence of any maintenance programme, or efforts to remedy the situation, other than the tarpaulin on the roof which would only provide a temporary solution. Paragraph 209 of the Framework states that where there is evidence of deliberate neglect of, or damage to, a heritage asset, the deteriorated state of the heritage asset should not be taken into account in any decision. Appeal Decision APP/J0540/D/25/3373080 3 14. Whilst there is a photograph of an external crack, there is no evidence, or photographs, of the interior of the building, which I was unable to access. Therefore, I have no information on the structure of the roof, including its condition or whether historic timbers remain. Thatch is one of the lightest of roofing materials and needs a modest framework, but a tiled roof would require more robust timbers. Whilst tiles are durable and are found on buildings surrounding the site, I have no evidence that the building could support tiles on the roof. I did see that the stonework was well pointed, and whilst there were some algae growing on the elevation facing the garden, presumably because of a lack of light and dampness, this could easily be removed. 15. The thatch has obviously failed and parts of it are falling away. The appellant contends that replacing the thatch is unsustainable because being located under a mature tree, it shortens its lifespan, meaning that it would rapidly decay, with costly maintenance. However, there is no substantive evidence about when the building was last thatched and the effect of the tree on its deterioration. 16. The appellant considers that maintaining the building with a thatched roof may result in it becoming beyond repair. However, there is only one quotation for each type of roofing material, although I note that within these two quotes there is a significant difference in the cost of thatching, as opposed to using tiles. 17. The quotation for tiling includes a description of proposed works but there is no drawing or section within the evidence showing the construction details and their effect on the appearance of the building. Cement boards are proposed for the gable ends but I have no evidence where exactly these would be sited. Moreover, cement infill is intended to be used. Cement is known to potentially cause damage to older buildings by trapping moisture which can lead to mould growth, timber decay and deterioration of both the mortar and the stonework. However, I have no evidence as to whether using modern materials in this way is suitable for this vernacular building. 18. The appellant refers to the proposed new roof being of similar proportions and size to the existing roof, so that it would maintain the scale and form, and reduce the need for constant maintenance. Whilst they state that other neighbouring outbuildings have been converted from thatch to tiles, I have not been provided with any examples or evidence of these. However, I did see a number of thatched buildings in Werrington, mostly residential properties, and which greatly enhance the appearance of the village. I also saw many buildings with tiled roofs. 19. Notwithstanding that the appellants consider that changing the roof material would preserve and secure the long-term use of the building, make it safer, and provide further living space for the house, I have not been provided with any compelling evidence that replacing the thatch would be appropriate for the building. Therefore, from the evidence before me, I conclude that the proposal would cause considerable harm to the NDHA which would harm its significance. 20. It would conflict with the Framework and PLP policy LP19 as set out above and PLP policy LP16 which requires development proposals to positively contribute to character and local distinctiveness and respect existing historic and built assets. 21. The Council do not refer to a specific policy within the Werrington Neighbourhood Plan 2024 to 2036, March 2025, but the plan includes supporting the maintenance and enhancement of characteristics and local distinctiveness within Werrington. Appeal Decision APP/J0540/D/25/3373080 4 Setting of the listed building 22. The grade II property, No 123 Church Street (No 123), is referred to in the listing1 as Werrington House. It is an imposing, double-fronted, two-storey dwelling with attic windows, that faces onto Church Street. The special interest and significance of this building, insofar as it relates to this appeal, is derived from its historic and architectural interest. Whilst the building was remodelled in 1820, it has early 18th century origins. The front is constructed of fine ashlar, and with its architectural detailing in the window openings and substantial door with fanlight and carved stone architrave, it represents an example of the wealth and quality of building in the early 19th century. To the rear it has a two-storey brick extension. 23. The Framework defines the setting of a heritage asset as the surroundings in which a heritage asset is experienced. The rear of No 123 is close to and visible from No 4 and from the NDHA. Therefore, the appeal site is within its setting. However, the NDHA, which is modest in height, is within the garden of No 4 with its tall sloping roof. There is a high boundary wall linking the house to the NDHA, next to a straight access road that runs parallel to No 4 and connects with the modern housing to the rear. Additionally, No 123 has a steeply pitched, tiled garage behind the house and next to the main entrance gates to Werrington Mews. This intrudes into the views between the NDHA and No 123. 24. Therefore, changing the thatch would have such a limited impact on the setting of No 123 that it would be preserved in accordance with the expectations of the Act and the requirements of PLP policy LP19, which amongst other things, requires the protection of designated heritage assets and their settings. Nor would there be any conflict in this regard with the objectives of the Framework which recognises the potential for harm to the significance of a designated heritage asset from development within its setting. For these reasons, I conclude that the proposal would not harm the setting of the grade II listed building, No 123 Church Street. Conservation area 25. The special interest and significance of the CA, insofar as it relates to this appeal, derives from its architectural and historic interest. Originally an agricultural community, mentioned in the Domesday Book, it would have initially consisted of a church, farm and scattered cottages. It has now expanded to include much 20th century development. The CA is a roughly linear area, and mainly residential in character, lined with numerous attractive vernacular buildings dating from the 17th century onwards. These would originally have had yards, workshops and store buildings to the rear. 26. Whilst not exceptionally verdant, there are trees and bushes which fringe the main road through the CA and soften and add interest to its appearance. Larger buildings tend to be built of stone and often have Collyweston slate roofs. There are several prominent thatched buildings which positively contribute to the character and appearance of the CA. 27. The building is small and provides a modest contribution to the collection of thatched buildings that remain within the CA. However, replacing the thatched roof with tiles would lead to harm through the erosion of historic and architectural detail. As a result, the proposal would fail to preserve or enhance the character or 1 List entry number:1126928 Appeal Decision APP/J0540/D/25/3373080 5 appearance of the CA. Therefore, it would fail to satisfy the requirements of the Act and paragraph 212 of the Framework. It would also conflict with PLP policies LP16 and LP19 as set out above. Other Matters 28. I have had regard to No 125 Church Street, a grade II listed building2 which is located to the front of No 4. This is a prominent thatched building whose significance in relation to this appeal, is the survival of an 18th century building, and an example of the importance of thatch as a roofing material from that period. Although the building is close to No 4 and is on the opposite side of the entrance into Werrington Mews from No 123, it is not experienced within the setting of the NDHA. Therefore, the appeal proposal would not harm the setting of this designated heritage asset. Public Benefits: conservation area and listed buildings 29. Paragraph 212 of the Framework advises that when considering the impact of development on the significance of designated heritage assets, great weight should be given to the asset’s conservation. Paragraph 213 goes on to advise that significance can be harmed or lost through the alteration or destruction of those assets and that any such harm should have clear and convincing justification. I find the harm to the CA to be less than substantial, and at the lower end of the scale, however, this is, nevertheless, of considerable importance and weight. I have found no harm to the other designated heritage assets. 30. Where a proposal would lead to less than substantial harm to the significance of a designated heritage asset, paragraph 215 of the Framework advises that this harm should be weighed against the public benefits of the proposal, including, where appropriate, securing its optimum viable use. The NDHA has been used for storage. The proposal would create a one-bedroom apartment which the appellant considers would enhance the value of the property. However, this is a private benefit. Whilst the appellant wishes to remove the thatch to make the building safe, this is not dependent on the roof being tiled. Additionally, whilst works to the building would provide some limited economic benefits, these benefits are not sufficient to outweigh the harm that I have identified to the CA. Conclusion 31. For the above reasons, and having regard to all other matters raised, the proposal would fail to preserve or enhance the character or appearance of the CA, contrary to the Act and the Framework. Furthermore, it would harm the significance of the NDHA. Consequently, the proposal would not be in accordance with the development plan. 32. I therefore conclude that the appeal should be dismissed. M J Francis INSPECTOR 2 List entry number:1162190