Change to Thatched Roofing Materials Planning Policy and Planning Appeals in England


RN2016/2, Apr 2016


This is one of a series of occasional IHBC Research Notes published by The Institute of Historic Building Conservation (IHBC).
IHBC Research Notes offer current and recent research into topics that we consider crucial to the promotion of good built and historic environment conservation policy and practice. The Notes necessarily reflect knowledge and practice at the time they were developed, while the IHBC always welcomes new case examples, feedback and comment to
research@ihbc.org.uk for future revisions and updates.


Executive Summary

1. This Note considers national planning policy guidance, sub-regional and local supplementary planning guidance and recent appeals determined by the Planning Inspectorate in relation to proposed changes of thatched roof coverings to discern the direction of heritage management and policy.


Introduction

2. Some members of IHBC have recently expressed concerns about the effect of planning appeal decisions in allowing changes to thatched roof coverings, either resulting in a change in the type of thatching material or a change to a different form of roof covering.

3. Since the start of the nineteenth Century there has been a steep decline in the number of thatched buildings in England, falling from an estimated 950,000 to fewer than 35,000 by 1960. [1] These losses have prompted government policy to ensure the continuation of this vernacular tradition, mirrored at local level by policy initiatives by some of those local planning authorities with a significant legacy of such buildings. Currently, there are about 24,000 listed thatched buildings remaining in England.

4. Long straw, combed wheat reed and water reed are the main thatching materials currently used in lowland Britain. [2] The materials are processed in different ways and differ in their on-site preparation, laying, and finished appearance. A change from one material to another may therefore have a detrimental impact on the appearance of the building and thus of its setting and local distinctiveness, and may harm the building’s authenticity and significance. Such changes are likely to be contrary to the principles enshrined in the National Planning Policy Framework (NPPF). [3]

5. As indicated, this Note considers the interpretation of national planning policy guidance; the scope of sub-regional and local supplementary planning guidance; recent appeals determined by the Planning Inspectorate in relation to proposed changes of thatched roof coverings and the direction of heritage management policy and practice that might be discerned from these.

6. The numbers of appeal cases specifically related to thatch have been relatively small by comparison with planning appeals as a whole, and notably so since the NPPF came into effect in 2012.

7. In 2014 the IHBC put out a call for information concerning thatching appeal cases and it continues to seek information on new cases as they arise in order to refine the content of a future edition of this Note. If sufficient numbers of past appeal cases predating the NPPF are also received, then in due course an Annex may review the general presumptions, policy basis and weight of material considerations given in appeals that predate the introduction of the NPPF in March 2012.


Evidence base for development management and in Local Development Frameworks

8. The specific basis on which individual development management decisions are made on applications for consent for a change of roofing material on thatched buildings remains ill-defined and further views from IHBC members on this issue would be useful. For the purposes of the current research note, since consented schemes are clearly not subject to further potential scrutiny via the planning appeal process, it is the appeals against refusal of listed building consent and the decisions by the Planning Inspectorate that are principally instructive.

9. It is also worth noting that perceptions can play a part in the decision making process with potential differences of opinion existing between lay Planning Committee members, heritage professionals and thatchers about the significance of historic thatch and what this means in planning policy terms.

10. The relatively low number of planning appeals concerning thatch may be explained by (in no order of priority):

  • The interest in and knowledge (or otherwise) about the significance and traditions of thatch within the local planning authority’s area;
  • The extent to which list descriptions of thatched listed buildings define the material type and detailed characteristics or features as a significant contribution to the special interest;
  • The extent to which there is homogeneity or diversity of thatching materials in a particular locality;
  • The policy content of approved Local Development Frameworks and subject specific local plan documents or for example county or district-wide Supplementary Planning Guidance (SPG);
  • The extent to which owners are encouraged to make applications for consent to alter thatch on listed buildings;
  • The extent to which alterations to thatch on listed buildings are undertaken without consent (that is, are unauthorised) - and the local planning authority’s response to this;
  • The extent to which the professional specialist officer’s recommendations for determining listed building applications relating to thatch are followed (and whether the decisions are delegated or are determined by the relevant council committee);
  • The state of supply of the appropriate thatching material at the time of the application.

11. Although there is a national policy presumption in favour of retaining traditional thatching materials and features that contribute to local distinctiveness (and in some cases a local presumption for retention through Local Development Frameworks), few listing descriptions define the specific thatching material used in the building. Some Listings describe the roof treatment only broadly in relation to ridges and dormers. This is a deficiency that weakens the necessary links between policy, significance and management.

12. Such imprecision is likely to depend on the date at which the building was originally listed. The primary purpose of early, long-standing descriptions was to aid identification rather than, as is the current practice, to better define what is significant about the heritage asset (that is, its special architectural and historic interest) and the reasons for statutory protection. [4]

13. This Note does not address other proposed changes to thatched buildings such as replacement of thatch with tile or slate, or replacement of other materials, such as corrugated iron, with thatch. [5]


Distribution of thatch

14. Little survey work seems to have been done to define the local or sub-regional (that is, individual local authority or county-wide) geographical distribution patterns of thatching materials based on geology, topography and agricultural practice. More information on this aspect would be welcome in future. English Heritage guidance from 2000 provides a map showing the distribution of numbers of thatched listed buildings by county but not the predominant thatch type. [6] [7] However, more detailed evidence of the regional distribution of different types of thatch is published in English Heritage’s Research Transaction Thatching in England 1700-1940. [8]

15. At one point in the 1990s several Suffolk local authorities regularly facing proposals to change types of thatching materials, proposed to test the hypothesis that distinctive patterns of location based on geology and topography might historically have been relate to the type of thatching material used. [9]

16. Distribution of thatch in Suffolk would traditionally have been based on the most readily likely availability of local materials. Based on the then known distribution of thatched buildings, and the knowledge of the conservation officers and local thatchers, it was suggested that the use of long straw was confined primarily to High Suffolk (the central county plateau) while the use of combed wheat reed and water reed was more confined to river valleys (and more to the south and east). Unfortunately substantiation of these assumptions by further detailed research was not completed due to other priorities and pressure on staff resources.

17. New Forest District Council is one authority that has identified three distinct geographical areas where particular types of thatch were used historically and remain discernible today and has produced guidance accordingly (see paragraph 61 below).

18. In the introduction to its thorough and detailed 2006 thatching policy and guidance, South Cambridgeshire District Council also highlights the survival of sub-regional diversity. Historically, the predominance of arable land made wheat straw the most widely available material, and long straw thatch, to a large extent characterized the built heritage of south Cambridgeshire. However, on the edges of fens in the north and northeast parts of the district some water reed had always been used.

19. Recently, questions of rarity and the geographical distribution of specific thatch types in Buckinghamshire were raised at appeal. This concerned the need for more information during consideration of a proposal for replacement of a long-straw topcoat (spar coat) with combed wheat reed laid to resemble long straw at Mulberry Cottage, Great Horwood in the area of Aylesbury Vale District Council (see Appeal Cases Dismissed page 16 et seq). [10]

20. Aylesbury Vale District Council [AVDC] felt that it would be instructive to determine how many long straw roofs remained within the District in order to put the case in a wider context. With funding from English Heritage, AVDC and Milton Keynes Council, a survey of the listed thatched buildings in the entire historic county of Buckinghamshire was undertaken.

21. The survey demonstrated that of the just over 900 listed thatched buildings in Buckinghamshire (the vast majority, if not all of which would have been thatched in long straw originally), just 31 genuine long-straw roofs survived (less than 3.5% of the total). At the date of this Research Note further detailed analysis is yet to be completed and may be included in a further update.

22. The results of this survey were used to support AVDC’s position during the subsequent appeal against refusal to grant listed building consent for the proposed change of material at case at Mulberry Cottage. In the appeal decision letter, the Inspector noted that:

‘There are other thatched buildings in the village, but the listed building is the only one still thatched in long straw. So it is rare in the village, as well as in the wider District and in the county. This makes its long straw thatched roof all the more important to preserve’ (emphasis added).


Policy Frameworks – the chronology of national guidance

23. The government’s recent streamlining of the planning system has resulted in a substantial reduction of the breadth and detail of policy guidance. The withdrawal of previous sound guidance as unnecessary so as not to overburden practitioners has not necessarily invalidated its continuing relevance and technical value.


The current position

24. Current planning policies for England are set out in the NPPF and came into operation in March 2012 when all previous policy was rescinded.

25. Policies for conserving and enhancing the historic environment are set out in NPPF Section 12, paragraphs 126 to 141.

26. The NPPF expects local planning authorities to set out a positive strategy in their local plans for the conservation and enjoyment of the historic environment; recognizing that heritage assets are an irreplaceable resource that should be conserved in a manner appropriate to their significance.

27. Paragraph 126 places the onus on local planning authorities to ensure that planning applicants describe the significance of any heritage assets affected (including any contribution made by their setting) and that the impact of a proposal avoids or minimizes the conflict between the conservation of a heritage asset and any aspect of the proposal.

28. Paragraph 132 makes clear that great weight should be given to the conservation of a designated heritage asset when considering the impact of a proposal on its significance. The more important the asset, the greater the weight should be and that significance can also be harmed or lost through alteration or destruction or development within its setting. As heritage assets are irreplaceable, any harm or loss requires clear and convincing justification.

29. The NPPF makes explicit the need to identify the level of harm to a designated heritage asset, and the public benefits that must be advanced to justify that harm. Development leading to substantial harm to or total loss of significance should be refused consent unless substantial public benefits can be demonstrated to outweigh that harm or loss. Proposals leading to less than substantial harm should also be weighed against the public benefits including securing optimum viable use of the heritage asset.


The status of policy

30. In recent years the status of policy and guidance has changed as publications previously issued by the government have been replaced by advisory documents from English Heritage and it successor, Historic England. By not carrying the government’s imprimatur, the advice may be considered by some to carry less compelling weight. It is therefore instructive to consider not only current advice but also a brief reprise of the doctrine that preceded it.


The evolution of policy

31. Government policy advice and doctrine on heritage management accumulated gradually over many years to be consolidated in the omnibus Circular 8/87 on Historic Buildings and Conservation Areas: Policy and Procedures. The bulk of the circular contained helpful advice but showed the Department of the Environment to have adopted an almost paternalistic attitude towards local planning authorities in advising them on their conservation work. [11]

32. The Circular was in operation for seven years until government guidance was updated as part of a suite of Planning Policy Guidance (Notes) [PPGs] one of which was Planning and the Historic Environment [PPG15] published in September 1994. Large parts of earlier heritage policy and guidance were reproduced as they had been in earlier circulars, but the particular advice given in Appendix C [12] regarding thatch is instructive because the text was only partly replicated in subsequent replacement guidance – PPS5 Planning for the Historic Environment: Historic Environment Planning Practice Guide.

33. Appendix C of PPG15 stated:

‘C.29 Thatch Thatched roofs should be preserved, and consent should not be given for their replacement by different roof coverings. Where mediaeval thatch survives with characteristic smoke blackening on the underside, it should be retained in situ and overlaid. When roofs are re-thatched, this should normally be done in a form of thatch traditional to the region, and local ways of detailing eaves, ridges and verges should be followed. Re-thatching roofs that have lost their thatch will require a waiver of building regulations in most cases, since they may not be allowed within 12 metres of a site boundary, but local authorities should be prepared to relax this rule if it does not constitute an unacceptable fire risk to other properties.’

34. Although withdrawn and no longer official government policy, the advice in PPG15 remains pertinent to historic building management as a consistent expression of sound principle, particularly regarding the impact and need for flexibility in the operation of other regulatory regimes.

35. PPS15 was unequivocal that consent should not be given for a change of roof covering from thatch. This reflected the precision of Section 16(2) of the 1990 Act. On the question of change from one thatch type to another (rather than to different types of roof covering, such as tiles) the use of the term ‘form of thatch’ is ambiguous.

36. Planning Policy Statement 5 (PPS5) was a short-lived guidance replacement for PPG15, swept away in only 20 months by the NPPF. During its short life the Practice Guide accompanying PPS5 became a more generalized statement about the preservation of all original roofing materials although thatch was still referred to in some detail. The historical and archaeological significance of multi-layered thatch roofs, particularly where the bottom layer is smoke blackened continued to be emphasised, with the injunction that significance should be retained by replacing only the topcoat. Furthermore, ambiguity regarding the type of thatching material to be used was removed by the introduction of the phrase ‘type and form of thatch rather than simply ‘form of thatch’ (as was used in PPG15). References to the impact of the Building and Fire Regulations were omitted.

37. In both PPG15 and the PPS5 Guide, the importance of maintaining regional thatching traditions and local ways of detailing eaves, ridges and verges were also highlighted. [13]

38. The PPG5 Guide also cited specifically Thatch and Thatching: A Guidance Note published by English Heritage in 2000. This describes the three main types of thatch; water reed, combed wheat reed, and long straw. It also says that local authorities should control by listed building consent the loss of thatch, when a change of material or style is proposed and that the onus should therefore be on the applicant to justify the need for such a change. [14] This centrally generated authoritative guidance continues to be a material consideration at appeal. It has particular importance in those areas where there are significant numbers of thatched listed buildings but where no local supplementary planning guidance has been produced.

39. After the restructuring of English Heritage and the formation of Historic England in April 2015 a number of further advisory documents were published by the latter, as replacements for the PPS5 Practice Guide cancelled on 27 March 2015. The current advice is no longer badged by CLG and DCMS. [15] [16]

40. One of the documents replacing the PPS5 Practice Guide is Historic England Advice Note 2: Making changes to Heritage Assets [HEAN 2], published in February 2016. With regard to materials for repair generally, Paragraph 11 states:

‘Original materials normally only need to be replaced when they have failed in their structural purpose. Repairing by re-using materials to match the original in substance, texture, quality and colour, helps maintain authenticity, ensures the repair is technically and visually compatible, minimises the use of new resources and reduces waste.’
Thatch is specifically mentioned in Paragraph 12:
‘Replacement of one material by another may harm significance and will in those cases need clear justification. Therefore, while the replacement of an inappropriate and non-original material on a roof, for example, is likely to be easily justified, more justification will be needed for changes from one type of thatch, slate or tile to another, or for changes in the way the material is processed, applied and detailed.’
Readers may care to note however that the advice in the draft of HEAN2 was more specific and arguably more helpful. [17]

41. The advice continues to emphasise the importance of using traditional materials so that the building’s significance is sustained. Changes from one type of thatch to another also need to be justified.

42. The way in which NPPF and post-PPG policy might be used to determine applications for listed building consent [18] is not as a substitute for the proper understanding of the particular significance of the building and the impact proposed changes might make. This is because each historic building will have its own characteristics, materials and external detailing. Furthermore, the structure and features of historic buildings are important considerations when understanding the significance of individual elements, based on what physically exists and information from documentary sources.


Principles and significance

43. HEAN2 draws attention to the philosophical reasons why society places a value on heritage assets beyond their mere utility and cross-refers to the English Heritage publication Conservation Principles - Policy and Guidance (2008) [19] which identifies four types of heritage value: aesthetic, communal, historic and evidential which can be used to analyse significance of heritage assets. The guidance contained in the Conservation Principles is intended to assist in deciding the most efficient and effective way of managing change to sustain a historic building’s overall value to society.

44. Assessment of significance is also covered in Part 4 of British Standard 7913: 2013, Guide to the Conservation of Historic Buildings. [20]

45. The Conservation Principles place particular importance on evidential and historical value, and archaeological interest. This should form part of the considerations of impact of proposals under the requirements of the NPPF and should form part of the evaluation of proposals involving thatch. Examples of such values may be related to, for example, thatching practices of the past; past use of materials; fixing methods and so forth. These in turn will have been influenced by past agricultural activities and social history. Thatch, despite its present cultural associations with a bucolic rural lifestyle, was considered historically to be of lower status than stone slate, slate or clay tiles.

46. The Conservation Principles may therefore be useful in considering:
aesthetic values associated with thatch: for example, the picturesque ‘poured-on’ look and the soft rounded forms of multi-layered thatch contrasted with the crisper lines of single layer thatch; archaeological values associated with thatch: for example, as an expression of our understanding of human history, memory and association; communal values associated with thatch: for example, the wider collective appreciation of local identity, spirit of place and regional or sub-regional distinctiveness; and, historical values associated with thatch: for example, the means of using local materials in construction; the continuity of craft practice and how society has come to value thatched buildings over time. .


Local Policy Frameworks

County-wide guidance

47. As might be anticipated, some counties with a large number of thatched buildings have produced policy or guidance (or both) concerning thatch at county council level. Some of this is of long-standing. Dorset Conservation Officers produced advice as long ago as 1996. [21] Hampshire County Council (undated, post 2003), where 14% of the county’s listed buildings are thatched [22]; and Wiltshire Council also produced guidance in the following decade. [23] Some of the most comprehensive guidance comes from Devon published in 2003 (see paras 51 to 59 below). [24]

The case of Devon
48. Thatch in Devon (2003) produced by Devon County Council is an exemplar (although the Hampshire, Wiltshire and South Cambridgeshire ones follow a similar pattern and offer equally useful advice) not least because as a roofing material, used in the county for over 600 years, it has survived better in Devon than in any other English county. There are about 4,000 thatched listed buildings (17% of the national total) although these are only a fraction of what once existed.

49. The document emphasises that although there have always been regional variations (as noted in the PPS5 Practice Guide) improved communications have eroded some of this local distinctiveness particularly in the last 50 years; [25] on the other hand, new materials and methods have been introduced to the county and a number of techniques and details formerly used in Devon are no longer used. As local traditions are not always fully understood this is one reason why it is important in Devon to preserve old thatching that might include evidence as yet unrecognised or not yet analysed.

50. Devon has a strong tradition of combed straw thatching, going back at least 600 years, using a method that was probably unique to the South West, known today variously as ‘combed wheat reed’, ‘wheat reed’ or simply ‘Devon reed’. It was produced in Devon by farmers and thatchers using tall varieties of wheat, special growing methods and special tools and techniques for harvesting, threshing and combing to ensure the best-quality roofing material.

51. Since the 1950s, water reed (Phragmites australis) has also been used extensively on Devon roofs, its introduction coinciding with a shortage of supply and decline in quality of local wheat straw. This fuelled the importation of water reed from abroad and encouraged complete replacement of straw roofs with water reed and, later, spar coating of straw roofs with water reed (nearly all grown outside England in recent decades). [26]

52. Specialist professional opinion within Devon’s local authorities has maintained that as water reed is not the main historic tradition in the county, Listed Building Consent is usually required to change the thatching material from wheat to water reed. Furthermore, water reed does not have the same links to local farming and local growing skills and has necessitated transport over relatively long distances and so has been considered a less sustainable repair material.

53. Strategic, regionally based advice such as produced by Devon County Council has principally identified the distribution of thatching materials based on geology, topography and climate (although less so patterns of agriculture) and emphasised the distinctiveness of characteristic local or sub-regional vernacular thatching details such as flush ridges, ridge peaks and dormers. While these features are not unique to Devon, they are characteristic of Devon thatch.

54. The policy emphasis has therefore been that the impact of proposals for alterations requires careful consideration by owners, agents and local authorities. The circumstances under which such alterations would be acceptable or not and require consent or not has also been made explicit. Particular attention has also been drawn to aspects of archaeological significance.

55. The Devon advice refers for example, to the traditional technique of spar-coating rather than complete stripping and re-thatching, which in some cases has contributed to the survival of numerous layers of historic thatch beneath the most recent overcoat. Historic thatch, some of which dates back to the fourteenth century, is an immensely interesting and precious archaeological resource, potentially of international interest in the field of archaeobotany for crops grown over the last 600 years; as well as providing evidence of old thatching techniques and methods such as the use of de-thorned blackberry stems, honeysuckle and tarred twine for fixings. This contributes to the historic interest and the archaeological record.

56. In Devon (as potentially the case elsewhere):

‘Some roofs preserve thatch that pre-dates the introduction of chimneys and first floors into houses. This thatch is usually pre-1550 and is smoke-blackened from an open hearth fire on the floor in the open hall. Smoke-blackened thatch is a rare and very important survival.’
(This again reflects the emphasis placed on smoke-blackening in the PPG15 and the PPS5 Guide).
‘In some cases this early thatch was laid with an eye to decorative effect when seen from the underside, the neatly-laid straw, the ties round the rafters and the battens forming a simple repeat pattern. Parts of the roof that were not above the open hall may have thatch that is equally early and interesting, but not smoke-blackened.’

57. The significance of the survival of the lower layers of thatch from mediaeval times until the Second World War maintained by regular spar coating appears to have been under appreciated. There is a case for arguing that the conservation of historic layers of thatch is essential for maintaining the significance of a thatched building, in terms of both its historic and evidential value, as well as, in some cases, its aesthetic value.


District-wide guidance

58. A small number of district councils have also published guidance or advice, usually where countywide guidance is absent. These include Aylesbury Vale District Council [27], Broadland District Council [28], South Cambridgeshire District Council [29] South Northamptonshire District Council [30], and South Somerset District Council. Several are also available as downloadable publications via the relevant local authority web pages. The advice from East Hertfordshire District Council is solely web-based [31].

59. The Aylesbury Vale District Council Advisory Guide Thatching Supplementary Planning Guidance (SPG) was cited by the Inspector in dismissing the appeal at Mulberry Cottage, 25 Spring Lane, Great Horwood [32] June 2014 (see page 17 et seq. below) as the explanation of the Council’s approach to the need for listed building consent where a change of material between combed wheat reed and long straw was proposed; and for a change of thatching method between any of the identified local styles. The Inspector concluded that the proposals would be contrary to the advice in the SPG and this was a material factor in the decision to dismiss the appeal.

60. The Broadland District Council guidance identifies the principal thatching materials used within its administrative area (predominantly water reed) and notes its principal characteristics and expected longevity. Erosion of regional traditions and the dilution of regional distinctiveness is also noted and attributed to thatchers from outside the area introducing details, such as ridge patterns from other areas. Although advice is given on acceptable standards of repair, the publication does not refer specifically to the impact of proposed alterations, other than to state that listed building consent would be required for the complete replacement of thatch.

61. New Forest District Council has also produced helpful guidance (2013) at District level [33] as 20% of its 1,600 listed buildings are thatched. New Forest has identified three geographical zones where the predominant type of thatch used both historically and currently can be identified:

  1. a coastal zone from the southern reaches of the Avon through the south of the area to the edge of Southampton Water and the River Test where the presence of marsh and more specifically managed reed beds led to the use of water reed (although suitable thatching reed is no longer obtained locally);
  2. the north western part of the area comprising the Avon Valley to the south of Salisbury, the villages to the west and the forest villages above the eastern slopes of the Avon valley. Long straw would have been used here in the past and generally the predominant material is still straw but in its combed wheat form - although a strong long straw tradition remains;
  3. the third zone covers the remainder of the area, encompassing much of the forest and agricultural areas to the north east. Long straw would traditionally have been used here but today much of the thatch is combed wheat reed with the occasional incidence of water reed.
This is clearly a useful basis for ensuring the local distinctiveness of thatching types is maintained.

62. Guidance from South Cambridgeshire District Council (2006) notes the historical predominance of long straw thatch as a consequence of geography and farming practice with water reed confined to the fen edges of the north and northeast of District. It also notes the introduction in the 1970s of combed wheat reed from the West Country replacing traditional long-straw thatch and the effect this had on the character and appearance to the buildings in question. The adopted policy context and guiding principles of the South Cambridgeshire guidance is particularly clear and precise. The 24-page document gives advice on reinstatement of thatch (from covering materials such as corrugated iron) and traditional repair; and clearly illustrates thatching techniques in use and the treatment of features such as ridges, dormers, verges and abutments. The use of thatch on new properties and extensions follows ‘The Dorset Model’ in which the roof construction is designed in such a way that, in the event of fire, the thatch is sacrificial. [34]

63. Guidance from South Northamptonshire District Council notes that thatch characterises many of its historic buildings, over 260 thatched examples of which are listed, and the traditional form in the district is long straw. It is noted that in the post war era there was a significant trend towards replacing long straw with combed wheat or Norfolk reed (water reed) creating a style of roof significantly different from the local vernacular tradition. Survey work by Northamptonshire County Council [35] showed that the rate of replacement of long straw roofs with combed wheat or Norfolk reed was so rapid that, if unchanged, it would result in the extinction of long straw thatch as a roofing material in the county within 30 years (the average life of a straw roof).

64. In East Hertfordshire, the current geographical distribution of thatching types is stated as appearing to be less marked. The Council’s web pages indicate that long straw was the traditional local thatching material by virtue of being the most readily available. Combed wheat reed is alien to East Hertfordshire. Water reed is a native material of East Anglia and not considered to be local. It was however used on a limited number of nineteenth century estate cottages and early twentieth century houses in East Hertfordshire.

65. South Somerset District Council appears to be the only local authority to provide district level building control advice in its published thatch guidance [36], reflecting concerns about the impact of regulatory regimes other than those concerned with heritage protection (as did the withdrawn advice in PPG15 (see above). [37]



Conclusion

66. Not all local authority guidance is dated and some publications appear to predate the introduction of the NPPF in March 2012 (and the withdrawal of the PPS5 Guide), and are likely to have been based on or related to the earlier PPG15 and possibly the English Heritage 2000 advice. It is therefore not clear how some of this sub-regional guidance now relates specifically to the phraseology of the NPPF. Furthermore, localised guidance, where it does exist, is not always cited in the relatively small number of thatching appeal decisions.

67. Local authorities have identified a need for county-wide or more localised guidance as a way of informing planning policy and to provide insights about the importance of locally distinctive thatching materials and traditions. Such publications may also reflect the difficulty of otherwise sourcing up to date advice.

68. There are also grounds for concern that as the most senior and experienced conservation specialists (some of whom will have written past local guidance) are being lost to retirement or redundancy (or indeed lost to the profession altogether), the authoritative nature of the specialist advice is consequently being eroded. Written guidance and its consistent application needs to be embedded within the local authority’s heritage management practices but is in danger of being lost over time as professional staffing changes.

69. It is noticeable that there is an absence of local authority supplementary planning guidance in many areas of lowland Britain where concentrations of thatched buildings might be expected to be located. It is unclear in those areas if the advice in the NPPF and the associated guidance are deemed sufficient to ensure appropriate heritage management of thatched buildings. The availability of advice (or otherwise) and status of supplementary planning guidance is not yet reflected in a sufficient number of appeal outcomes to assess if this has had a bearing on adjudications by the Planning Inspectorate (see below).


Development Management

70. If the significance of thatched buildings is to be properly protected it is important for specialist conservation staff within local planning authorities to be engaged in the registration of planning and listed building applications for works to thatched buildings to ensure that the necessary level of information and/or specification of the works has been submitted.

71. The level of detail submitted with applications for listed building consent on thatched buildings needs careful consideration. Although some information, particularly elevations, can be conveyed by drawings, some may best be set out in a specification. This should include the proposed material (distinguishing between wheat and triticale straw [38]), coat thickness, details such as ridge and verge design, as well as the proposed means of securing the thatch, for example, whether traditional split hardwood sways, spars and liggers will be used or modern metal or plastic alternatives; and whether thatch will be tied to the rafters in the traditional manner or whether modern method of fixing such as steel spikes or wires secured with screws driven into the rafters will be used. These details have implications for maintaining traditional craft skills.


72. The appropriate degree of control over the works may require the imposition of conditions. There is little specific published advice regarding the appropriate phraseology of conditions for planning permission or listed building consent related to thatching other than that generically those conditions should be necessary; relevant; enforceable; precise; and reasonable. However IHBC has published a Guidance Note on the framing of conditions for listed building consent, which is germane to thatch and to which readers should refer. [39]

73. In the section on materials in the LBC Guidance Note referred to above, examples of pertinent draft conditions are given related to the need for new roof coverings to precisely match (and specifying the type of thatch); construction methods and materials for features such as dormers or cappings; and the need for recording of existing historic thatch or archaeobotanical analysis.

74. Where proposals for works have been the subject of a refusal of consent and a subsequent appeal, the Institute would be pleased to learn of any specific conditions suggested by the local planning authority or imposed by the Planning Inspectorate where an appeal has been upheld, for incorporation in a future edition of this Research Note or to inform the LBC Guidance Note.


Issues to emerge from Planning Appeals

Main Issues

75. The common main issue identified by the Inspectorate in thatching appeal decisions is whether the proposed works would preserve the special architectural or historic interest of the listed building or any features of special interest which it possesses. [40] This is the statutory test of the 1990 Act and should have primacy over the less well defined terminology of the NPPF where the objective is to determine the impact on significance and character but as the PPS5 Guide and Good Practice Advice 2 (GPA2) make clear this may also potentially turn on the historical and archaeological evidence.


Subsidiary issues
Contribution to significance
76. In two recent appeals, the contribution that thatch makes to the significance of a heritage asset was examined in some detail. In the Aylesbury Vale case (APP/J0405/E/14/2213476), the Inspector found that ‘Due to its scale, form, materials, alignment and detailing, the long straw thatched roof of the listed building is one of its most important features, which it is desirable to preserve. It contributes positively to the significance of the heritage asset as a historic building which was built using traditional local materials and traditional methods’ and that ‘due to its evidential, historical, aesthetic and communal values, great weight should be attached to the conservation of the existing long straw thatched roof’.


77. In the Wiltshire case (APP/Y3940/E/13/2207654), the Inspector concluded that ‘in this case whilst combed wheat reed may not have been the original roofing material, it nonetheless reflects a continuation of the use of wheat straw as a thatching material, which adds to its value and special interest. In addition, the combed wheat reed thatch adds to our understanding of the evolution of the building and, whilst not specifically referred to as such within the listing description, it is not a matter of dispute that this material was in place at the time of listing. Accordingly, for these reasons, I consider that the current thatching material is of considerable importance to the historic character and significance of the listed building.’

Effect of a change of thatch material on significance
78. It follows that if the thatch makes an important contribution to the significance of a heritage asset, then changing the thatch covering will have an impact on significance. In the case of St Nicholas Cottage, Chaldon Herring, Dorset (APP/B1225/E/12/2187662), the Inspector considered that ‘the total loss of the existing thatch material… would cause substantial harm as set out in paragraph 133 of the Framework’ [the NPPF].

79. In the Wiltshire case the Inspector considered ‘that the proposed use of an entirely different thatching material for the top coat of the thatch would not make an appropriate contribution to the evolution of this vernacular building, but would be significantly detrimental to its authenticity. It would materially diminish the historic character of the listed building and would have a harmful impact on its value as a heritage asset.’.

80. Similarly, in the Aylesbury Vale case, the Inspector considered that ‘Because the proposed thatch would not be the genuine article, the authenticity and integrity of the asset, and thus its significance would be unacceptably eroded.’ In both these cases however, the level of harm was considered to be less than substantial.

81. In the East Northamptonshire case (APP/G2815/F/12/2168063), the Inspector considered that ‘the use of reed thatch introduces an alien and uncharacteristic element that is of significant harm to the appearance and to the architectural and historic interest of the listed building. Furthermore, its presence in such close proximity to several other listed buildings is harmful to their setting’ and concluded that ‘the unauthorised works cause significant harm to the special interest of the Butchers Shop and to the setting of nearby listed buildings.’ The use of the term ‘significant harm’ is out of kilter with the terminology in the NPPF, which refers to ‘substantial harm’.

82. This appeal was determined shortly after the introduction of the NPPF and it is not clear whether the Inspector intended to imply that the work amounted to substantial harm, but was not fully conversant with the new terminology. However, given the literal meaning of the two words it would not be unreasonable to consider that in this case ‘significant’ is synonymous with ‘substantial’.

83. The notion that a change of thatching material is harmful to the character or significance of a heritage asset is also evident in several appeal decisions pre-dating the NPPF, such as the South Somerset case (APP/R3325/E/04/1148702) in which the Inspector concluded ‘that a change in thatching material must be regarded as harmful to the character of the building.’

Justification of harmful change
84. The NPPF directs that proposals that would cause substantial or less than substantial harm to the significance of a heritage asset should not normally be permitted unless (in the case of substantial harm) the harm is necessary to achieve substantial public benefits or are essential to bring the heritage asset back into viable use (paragraph133), or in the case of less-than-substantial harm, this harm has been weighed against the public benefits of the proposal, including securing its optimum viable use (paragraph 134).

85. In both the Aylesbury Vale and Wiltshire cases, the Inspector concluded that the appeal properties were already in their optimum viable use as dwellings, and that this use would not be threatened if the appeal were dismissed. Furthermore, in the Wiltshire case, the Inspector stated that, although the appeal proposal would bring public benefits such as improving the appearance of the building, and supporting and sustaining the thatching industry, similar public benefits would arise from the use of combed wheat reed, so the proposal was not essential to achieve those benefits.

Informal advice and reputational risks
86. The issue of cost is a factor frequently advanced by applicants when applying for a change of thatching material, and prior to the introduction of the NPPF there is some evidence that Inspectors considered this to be a material factor in their decision. However, post NPPF, a clearer picture seems to be emerging. In the Wiltshire case, the Inspector expressed some sympathy with the appellant (who had already purchased water reed for her roof), but considered that any additional expense that might be incurred should the appeal fail would be a private matter and that obviating such expense did not constitute a public benefit. Similarly, in the East Northamptonshire case, the Inspector found that ‘the appellant has effectively incurred this cost himself by carrying out unauthorised works that harm listed building interests. The argument of excessive expense does not justify retention of the unauthorised works.’

87. In the Dorset case, the Inspector weighed the substantial harm that would be caused by the total loss of the existing combed wheat reed thatch and its replacement with water reed against the public benefit of conserving the building. Taking into account the urgency of the work (given the extremely dilapidated state of the building), the fact that there was a well-documented shortage of combed wheat reed at the time, and the fact that listed building consent had already been granted for complete removal of the combed wheat reed thatch to enable reconstruction of the roof timbers, he considered that the additional harm of allowing the use of water reed (instead of combed wheat reed) on the new roof was justified. He was at pains to point out that the harm to the heritage asset was justified by the particular circumstances of the case, and that the decision ‘should not been seen as a statement of the need for policy change or change of approach in principle.’

Age
88. Appellants sometimes raise arguments about the age of thatched roofs related in particular to claims that re-timbering had been undertaken in the relatively recent past – perhaps within the preceding 40-50 years – and that the thatch was therefore of little historic significance. However, where such roofs have been thatched using the methods and materials traditional to that area, a number of Inspectors have found that the continuity of craft tradition does contribute positively to the significance of the building.

89. In the Aylesbury Vale case, the Planning Inspector therefore rightly stated that, even if the thatch was later than the structure ‘due to its evidential, historical, aesthetic and communal values (…) great weight should be attached to the conservation of the existing long straw thatched roof’.

90. In the Wiltshire case, even though the current combed wheat reed thatch was a comparatively modern (mid twentieth century) spar coating of what was originally a long straw roof, the Inspector did not accept that this strengthened the case for permitting a further change of material to water reed, and stated that the alteration from long straw to combed wheat reed ‘took place before the building was listed and does not provide an adequate reason to make further changes to the building that would affect its historic character. In addition, whilst significant, the impact of this previous change on the character of the building was mitigated to some extent by the continued use of a wheat straw thatch.’

Rarity in a local context
91. In the Aylesbury Vale case, the Inspector considered that relative rarity of long-straw thatch within the village, district and county was a crucial aspect of significance and highlights the advice in the NPPF that an ability to determine rarity should form part of the local planning authority’s positive strategy for the conservation and enjoyment of the historic environment, [41] and identify and assess the particular significance of any heritage asset that may be affected by a proposal. [42] [43]

92. Similarly, the Inspector in a case in New Forest (APP/B9506/E/08/2092965) considered that the fact that so many roofs in the locality had already been changed to water reed ‘only goes to make those [combed wheat reed] roofs remaining unaltered all the more rare.’

Longevity
93. An assessment of how long a roof (or slope) had already lasted and how much longer it could continue to function adequately before replacement in whole or in part and the likely lifespan of alternative replacement thatching materials are issues addressed in a number of appeals. In most cases, one of the reasons appellants cite for wanting to change the type of thatch on their roof is that they believe the proposed thatch material would be more durable (and hence cheaper in the long run) that the existing type of thatch. [44]

94. In making assessments regarding likely longevity of thatch, Inspectors have made reference to published sources of information, the advice of Historic England, the different opinions of thatchers representing both sides in the appeal, and the condition of other roofs in the locality. Several Inspectors have concluded that there is insufficient evidence to demonstrate that one particular material will last longer than another.

95. In the Aylesbury Vale case, the Inspector concluded that ‘As the performance of thatch would be affected by the quality of the thatching material, the skill of the thatcher, and the site specific circumstances, it is difficult to draw comparisons between one type of thatch and another. So, there is insufficient evidence to show that the proposed spar coat would outlast long straw’. Similarly, in the Park Cottage case the Inspector found ‘that the balance of the evidence before me does not clearly demonstrate that, in the particular case of the appeal property, there is a reasonable probability that water reed would be more durable than combed wheat reed.

96. In any case, even if there were evidence to support the suggestion that the proposed alternative thatch would last longer than the existing material, the resulting cost saving would be a private benefit rather than a public benefit, and as explained above, this would not be a valid reason to justify harm to the heritage asset.

‘At-risk’ status
97. This is not of its self a justification for a change of materials and arguments that, for example, some thatch may have already slipped with a consequential impact on the stability of the supporting walls would need to be backed by structural engineering evidence. Other evidence such as the use of tarpaulins to address leaks in the roof would also need to be advanced.

98. In the Purbeck District Council case (see below) 2013, it was argued that although the loss of thatching material causes substantial harm, the at-risk status of the building and the early availability of the alternative thatching material was justified in the interest of the timely preservation of the building and the setting of the conservation area.

Authenticity
99. There is a subtle but important distinction between the overall appearance of a thatched roof and its character and integrity, which embrace qualities apart from the visual ones. Although, in skilled hands, one type of thatch might be made to look similar to another, several Inspectors have concluded that authenticity and integrity should be maintained when re-thatching. In the New Forest case, the Inspector stated that ‘one of the important purposes of listed building protection is to help distinguish the genuine article from imitation.’

100. In the Aylesbury Vale case, the Inspector concluded that the use of ‘reed straw thatch made to look like long straw’, should not be permitted ‘Because the proposed thatch would not be the genuine article, the authenticity and integrity of the asset, and thus its significance would be unacceptably eroded.’ In the Wiltshire case, the Inspector concluded that that the use of water reed for spar coating the property ‘would be significantly detrimental to its authenticity. It would materially diminish the historic character of the listed building and would have a harmful impact on its value as a heritage asset.’

Setting
101. This is to some extent dependent on location and particularly with regard to properties within Conservation Areas. As the NPPF attaches weight to conservation areas as designated heritage assets, the particular issue of concern within them is the impact on character and appearance. In the Aylesbury Vale case, although there would be little visible difference between the types of thatch proposed, the Inspector concluded that the character of the Conservation Area would fail to be preserved.


CONCLUSIONS

Thatched buildings are an acknowledged precious and finite heritage assets but as a resource they now represent only a small fraction of the picturesque, vernacular tradition that existed 200 years ago.

Changes in agricultural practices and the supply and use of thatching materials and techniques from beyond the locality, applied in areas with a clear historical tradition of locally sourced materials erode the significance and local distinctiveness of thatch as well as risking the loss of archaeological, historical, artistic, and archaeobotanical interest.

Policy under the NPPF, and the advice on implementation included in GPA 2 and HEAN2 is crucial to the appropriate heritage management of changes to thatched buildings. The policy is well supported by the associated English Heritage guidance (2000); however the meaning of this in planning appeals is yet to be fully evaluated as few clear trends have yet emerged.

Sub-regional (usually county) and local guidance from local planning authorities is essential as a basis for understanding questions of rarity and geographical distribution in a local/area context; and identifying the characteristic detailing that defines local distinctiveness.

The expertise essential to understanding the resource at local authority level, including necessary research to better understand the assets, the production of guidance and its consistent application in development management in often not sufficiently embedded within the authority and is being eroded further by the loss of conservation specialists.


Bob Kindred MBE BA IHBC MRTPI IHBC





Acknowledgments

Particular thanks are due to Alison Henry of Historic England for many helpful comments and additions to the draft. Thanks are also to David Andrews, Mark Clitherow, Anne Davies, Libby Kirkby-Taylor, Andrew Minting, Judith Shepherd, Greg Venn and Robin Uff for assistance with information contributing to the compilation of this Research Note together with participants in the Essex CC Cressing Temple Thatching Day, October 2014.


Endnotes

[1] Thatch and Thatching: A Guidance Note English Heritage (2000) p4, Table 1, gives the estimated number of thatched buildings by region in 1800, 1862-3 and 1960, but the 1960 survey is known to have been incomplete.

[2] This Note does not address relatively rare roofing types such as heather, flax or rye roofing materials. These can occasionally be encountered sandwiched as middle coats in old roofs.

[3] From to 27 March 2012 the date on which the NPPF came into effect, cancelling previous government planning policy.

[4] These are sometimes known as the ‘legacy’ designations, prior to best practice descriptions and potentially covering thousands of vernacular buildings listed over the period from the 1950s to the 1990s.

[5] Occasionally note when a building at risk case is resolved.

[6] Thatch and Thatching, p3. This guidance note remains extant but may be re-issued/revised as Historic England guidance in due course.

[7] The English Heritage (sic) Research Transaction volumes contain much more detailed information about distribution of the different types of thatch.

[8] Cox, J and Letts, J B (2000); Thatch: Thatching in England 1940-1994, English Heritage Research Transactions: Research and Case Studies in Architectural Conservation, 6; London, 1999: James & James.

[9] Unpublished discussions by Suffolk Conservation Officers Forum

[10] Following the refusal of the LBC, the survey was undertaken before the appeal, and the results (that is, low total number of long straw roofs surviving in the county and the fact that Mulberry Cottage was the last surviving one in that particular village) were a material factor in the Inspector’s decision.

[11] Delafons, J Politics and Preservation, E&FN Spon, 1997, p167.

[12] PPG15 Planning & the Historic Environment was replaced by PPS5 Planning for the Historic Environment which was promptly replaced by the NPPF.

[13] In this context ‘local’ is taken to mean both ‘local to the immediate area’ and also ‘local to the wider region’. The term ‘local ways of detailing’ is not considered of any lesser importance than ‘regional thatching traditions’.

[14] The phraseology as a policy is ambiguous in that it could be construed as opposition to a non-thatching material (for example, to tile) rather than from one form of thatch to another, but is generally taken to be the latter.

[15] Historic Environment Good Practice Advice in Planning Note 2 - Managing Significance in Decision-Taking in the Historic Environment, English Heritage, March 2015

[16] PPG5 Good Practice Guide, paragraph 142-3.

[17] The consultation draft of HEAN2, April 2015, advised: ‘Replacement of one material by another, for example on roofs, may result in a loss of significance and will in those cases need clear justification. Therefore, while the replacement of an inappropriate and non-original material is likely to be easily justified, more justification will be needed for changes from one type of thatch, slate or tile to another. For thatch, for example, preserving the covering on multi-layered roofs, particularly where the bottom layer is smoke-blackened, is likely to be necessary in order to maintain the historic and archaeological significance of the building. Only the topcoat may need to be replaced. Following the type and form of thatch traditional to the region with local ways of detailing eaves, ridges and verges will sustain the building’s significance. English Heritage has published specific guidance on thatching: Thatch and Thatching: A Guidance Note (English Heritage, 2000)’.

[18] Historic England Advice Note 2- Making Changes to Heritage Assets, February 2016.

[19] Conservation Principles: Policies & Guidance, English Heritage, 2008

[20] Guide to the conservation of historic buildings BS 7913:2013, British Standards Institution, Second edition, December 2013.

[21] http://www.traditional-thatch.org.uk/content/wp-content/uploads/2013/06/Dorset-Thatching-Report.pdf accessed 07-10-2014.

[22] http://www.traditional-thatch.org.uk/content/wp-content/uploads/2013/06/Hampshire-thatching_booklet.pdf accessed 07-10-2014.

[23] http://www.wiltshire.gov.uk/thatching.pdf accessed 07-10-2014.

[24] http://www.traditional-thatch.org.uk/content/wp-content/uploads/2013/06/Thatch-in-Devon.pdf accessed 07-10-14.

[25] Written in 2003, so now over 60 years.

[26] Turkey, Hungary and Austria were common sources.

[27] Approved 30 August 2000 following public consultation, published May 2006.

[28] http://www.traditional-thatch.org.uk/content/wp-content/uploads/2013/06/Broadland-District-Council-Planning_Advice_Note_14_-_Thatching.pdf accessed 07-10-14.

[29] Thatch and Thatching in South Cambridgeshire, Document DCV0043, Approved 2006, South Cambridgeshire District Council 2007

[30] http://www.southnorthants.gov.uk/snc_doc_SPG_-_Thatching.pdf accessed 08-10-14.

[31] http://www.eastherts.gov.uk/index.jsp?articleid=15846

[32] Appeal Ref: APP/J0405/E/14/2213476.

[33] https://www.newforest.gov.uk/media/adobe/h/h/HistoricBuildings-thatching_00145.pdf accessed 08-10-14.

[34] Ibid.

[35] Unpublished study.

[36] http://www.traditional-thatch.org.uk/content/wp-content/uploads/2013/06/South-Somerset-Thatch.pdf accessed 07-10-14.

[37] PPG15 Appendix c28.

[38] A hybrid cereal produced by crossing wheat and rye, usually grown as a fodder crop.

[39] Guidance Note on Listed Building Consent – Standard Conditions, Reasons and Informatives, Institute of Historic Building Consent, GN 2015/1 March 2015.

[40] Planning (Listed Buildings & Conservation Areas) Act 1990 Section 16(2).

[41] NPPF Para 126.

[42] NPPF Para 129.

[43] Various other pre-NPPF Inspectors also referred to rarity as all the more reason to preserve a particular type of thatch.

[44] In the Great Horwood, Buckinghamshire (AVDC) case Appeal dated 05/06/2014 Ref: APP/J0405/E/14/2213476, the Inspector observed that a ‘lack of a reference to the type of thatch does not imply that it is not of significance’.


Appendix A

Appeal summaries post-dating the introduction of the NPPF

(These are case résumés and readers should also direct themselves to the full decision letter.)

EXEMPLAR Appeals Dismissed

Case 1

‘Complete re-thatch (see attached letter from Neil Painting, master thatcher and re-submission document) raising LH chimney to necessary height.’Appeal dismissed 5 June 2014. Appeal Ref: APP/J0405/E/14/2213476 Mulberry Cottage, 25 Spring Lane, Great Horwood, Buckinghamshire MK17 0QP Aylesbury Vale District Council.

Main issue

Whether the proposed works would preserve the special architectural or historic interest of the listed building or any features of special interest which it possesses.

Summary

Listed Grade II in 1984. The traditional form and materials of the long straw thatched roofed and timber-framed 1 and 1⁄2-storey mainly seventh and eighteenth century dwelling are important to its special architectural interest and that of Great Horwood, a village of mediaeval origins. Destruction by fire of other buildings in the late eighteenth century resulted in a village core mainly characterised by brick buildings of around that date. Even so, number of other scattered thatched timber-framed buildings survived from the earlier period.

The scale, form, materials, alignment and detailing of the long straw thatched roof was one of its most important features; desirable to be preserved and contributing positively to the significance by being built of traditional local materials using traditional methods.

A lack of reference to the type of thatch did not imply that it was not of significance and of the other thatched buildings in the village, it was the only one still thatched in long straw, therefore being rare in the village, as well as in the wider District and in the county. This made its long straw thatched roof all the more important to preserve.

The view of the appellant’s adviser was that the entire roof was re-timbered and replaced in the 1980s when a 2-storey extension was said to have been added, and by being only about 40 years old had little significance despite a late twentieth century 2-storey extension not being much in evidence. The oldest part of the building may well include historic fabric including pole rafters and thatch layers from about the seventeenth century. These were significant because of their age and materials. Even if the thatch were later, great weight should be attached to conservation of the existing long straw thatched roof because of its evidential, historical, aesthetic and communal values.

Although described as ‘at risk’, with some slipped thatch that the walls would be put out of balance, this was not supported by structural engineering evidence, and in the absence of tarpaulins an its use as a dwelling suggested the roof did not leak.

Despite some gulleying on the south-facing roof slope, the appellant’s thatching adviser considered that the north-facing slope had already lasted about 18 years with minor repairs and could last another 3 to 5 years, giving about 21 to 23 years life overall reflecting quite well on the longevity of the existing long straw thatch.

The works are described as a complete re-thatch, but the design and access statement says that the works include the replacement of a spar coat of the mixed and jumbled long straw style of thatch with a mixed heads and butts cereal straw spar coat in the long straw style. The reasons given for the change in the method of thatching were to reduce the amount of straw required and to increase the longevity of the thatch.

PPS5 was cited concerning sustaining a building’s significance through the type and form of thatch traditional to the region and the need for justification for a change from one type of thatch to another in line with the relevant English Heritage guidance note, thus the onus was on the applicant to explain the need for change. Aylesbury Vale District Council’s Advisory Guide on Thatching also explained that listed building consent would normally be required for a change of material between combed wheat reed and long straw, and for a change of thatching method between any of the identified styles.

There was no suggestion that water reed would be used. Long straw and combed wheat reed however were prepared from the same raw material, but processed in different ways, and differed in their preparation, laying, function, and finished appearance. The appellant’s statement had said that the thatching material would not be combed wheat. If long straw had been proposed listed building consent would not have been required.

It transpired during the hearing that the roof would be recoated using uncombed cereal straw, laid dry, with heads and butts showing on the surface. The material would have some of the characteristics of combed wheat reed because it would retain much of the tubular nature of wheat or other cereal reeds, but it would not be dressed into place with a leggat. Because it would not be threshed material that is shaken into a layered bed, carefully wetted and allowed to steep (which makes the material pliable), and it would not be drawn from the bed and formed into yealms, it would not be long straw.

Thus, the thatch would be a hybrid style, but not the hybrid thatch identified in the local authority’s guidance, that is, it would be a reed straw thatch made to look like long straw.

It was the view of English Heritage and the Conservation of Traditional Thatch Group that as most of the waste products of combed wheat reed are discarded before delivery, and most of the waste products of long straw are discarded after delivery, broadly the same sized square of wheat (or other cereal crop) is grown for each type of thatching. Whilst the proposed thatching style would be somewhere between combed wheat reed and long straw, there was little evidence that it would make better use of available thatching straw supplies. Although the appellant’s adviser considered the natural decay of uncrushed thatching material would be slower than in long straw (and the spar coat last longer) little evidence was provided to support that view. As the performance of thatch would be affected by the quality of the thatching material, the skill of the thatcher, and the site specific circumstances, it was difficult to draw comparisons between one type of thatch and another and insufficient evidence to show that the proposed spar coat would outlast long straw.

The argument that relatively frequent repair and replacement of the spar coat is not a permanent feature and not a loss of historic fabric ignores the protection offered to the more historic thatch layers below. Continuing this method over many years contributes positively to its cultural value and special interest.

As the proposed thatch would not be the genuine article, authenticity and integrity, and thus significance would be unacceptably eroded. Moreover, there was no shortage of skills and materials to provide a long straw spar coat.

CASE 2

Preamble - Park Cottage, Milton, Wiltshire (see case below)

The following appeal was originally allowed by the Planning Inspectorate in March 2014 but was subsequently quashed following a Judicial Review because the Inspector had erred for the following reasons:

a) failing to adequately apply the statutory duty in Section 16(2) of the 1990 Act;

b) failing to adequately consider the relevant policy requirements at paragraph 134 of the NPPF;

c) taking into account in error, the reasonableness of the appeal property owner’s desire to replace the wheat reed thatch with water reed on the basis that it was a longer term solution without having made findings on the availability or otherwise of good quality wheat reed and whether the apparent difference in performance between water reed and wheat reed was due to other factors separate from the inherent quality of wheat reed

d) failing to adequately consider another property, Hill Cottage, brought to the Inspector’s attention during the site visit.

‘Strip back top coat of combed wheat reed thatch and replace with water reed’. Appeal dismissed 20 April 2015 superseding that issued on 20 March 2014 and subsequently quashed by order of the High Court. Appeal Ref: APP/Y3940/E/13/2207654 Park Cottage, Milton, East Knoyle, Salisbury SP3 6BG Wiltshire Council.

Main Issue

Whether or not the proposal would: preserve the listed building, any features of special architectural or historic interest that it possesses, or its setting; and preserve or enhance the character or appearance of the Conservation Area, including in respect of the setting of other listed buildings nearby.

Summary

Listed Grade II in 1987. Located within the East Knoyle and Milton Conservation Area in relatively close proximity to a number of other listed buildings in a hamlet detached from the main part of East Knoyle. Properties are informally and loosely grouped with variety of designs, ages and sizes where steep changes in levels and the large number of trees imposes a predominantly rural appearance and sylvan character to the locality. The high proportion of thatched properties contributes positively towards this and is particularly important to the significance of the Conservation Area. The appeal building in an elevated and visually prominent position is set back from the road, at the heart of the settlement. This setting and the positive contribution that the building makes to the setting and significance of other buildings nearby, and to the character and appearance of the Conservation Area, also contribute to the significance of the appeal dwelling.

The appellant contended that the present thatched roof may previously have been tiled but a photograph of the property from around 1910 indicated that it was thatched in long straw at that time with nothing to indicate that it not remained so. At some point towards the latter part of the twentieth century, the roof had been re-thatched in combed wheat reed reflecting a wider change in thatching practice, allied to alterations in agricultural production and a more general move away from long straw in the area at that time.

The nature of the top coat of thatched roofs is that the material has a limited lifespan and is renewed from time to time. In this case, whilst combed wheat reed may not have been the original roofing material, it nonetheless reflected a continuation of the use of wheat straw as a thatching material, which added to its value and special interest. In addition, the combed wheat reed thatch adds to our understanding of the evolution of the building and, whilst not specifically referred to as such within the listing description in place at that point. The Inspector therefore considered the current thatching material to be of considerable importance to the historic character and significance of the listed building.

The need to replace the top coat was not disputed and there was evidence of water penetration within the dwelling despite some repairs. One elevation of the roof slope was in better condition than the other and could potentially last longer before needing to be renewed but was considered sensible to re-thatch the entire roof with a new spar coat.

It was proposed to replace the top layer of the existing combed wheat reed thatch with water reed. It is not disputed that the skill of the thatcher could ensure that the difference in appearance between these two materials would not be significant and the Inspector considered that the proposal would not alter the appearance of the building, or materially affect its setting or the setting of other listed buildings nearby, or the appearance of the area.

Notwithstanding the Inspector’s finding that the combed wheat reed thatch is an important feature, the previous change from long straw to combed wheat reed was significant but had taken place before the building was listed and was not an adequate reason to make further changes to the historic character of the building. Also, whilst significant, the impact of this previous change on the character of the building was mitigated to some extent by the continued use of a wheat straw thatch.

Whilst it is not intended to strip the roof completely and the under-straw would be preserved, a replacement of the spar coat with water reed would result in the use of a thatching material that was traditionally used more frequently in other parts of the country. As farming and thatching practices have changed, together with the requirements of owners of thatched buildings, this situation has altered. Nevertheless, notwithstanding some exceptions in Milton, the use of water reed was not historically prevalent in the local area and, from the evidence before me, has not been used previously on this building.

The proposed use of an entirely different thatching material for the top coat would not make an appropriate contribution to the evolution of this vernacular building, but would be significantly detrimental to its authenticity. It would materially diminish the historic character of the listed building and would have a harmful impact on its value as a heritage asset and would cause some harm to the significance of the Conservation Area and would be contrary to the Council’s Core Strategy Policy CP58, which seeks to protect the historic environment.

The lifespan of the existing and previous thatched coating were not in dispute. Intervals between re-thatching of the appeal dwelling have been notably shorter than for some other properties nearby and although evidence about the relative longevity of combed wheat reed and water reed was conflicting the relative performance of different materials elsewhere, supported the view that, in many cases, water reed can outlast combed wheat reed although a number of variables including site specific conditions (for example, climate, rainfall, orientation of the building, design and pitch of the roof slope), as well as the quality of the materials and skill of the thatcher would play their part. There was therefore a reasonable probability that water reed would be more durable than combed wheat reed.

The lifespan of the existing thatch was not considered to have been excessively short and even if the longevity of water reed were to be greater the Inspector considered it likely that future performance of combed wheat reed could not reasonably be expected to be so poor as to justify the harmful use of water reed in this particular case.

Regarding past shortages of available good quality combed wheat reed there were strongly held views and conflicting evidence was presented about current and future availability of combed wheat reed but English Heritage and a local independent thatcher confirmed that supplies of combed wheat reed could still be sourced, and the Council also confirmed that it had not received other applications or enquiries to alter thatching materials on buildings elsewhere, in contrast to the time of the shortage in 2008.

Overall, the Inspector considered that there is a shortage of combed wheat reed not adequately demonstrated support for the use of water reed in this case. Addition, with regards to the timing of the appeal decision in relation to the harvest and the stocks remaining, the undisputed evidence presented by English Heritage, about the storage methods of the materials and the consequent implications for the quality of the product, lent further support to the Inspector’s opinion.

Mitigation

The suggestion that, any harm identified to the heritage assets could be appropriately mitigated by the use of a condition to limit the consent granted to the lifespan of the proposed thatch and restrict the subsequent replacement of the spar coat in water reed without a further consent would meet the relevant tests in the PPG. If consent was granted and the top coat replaced with water reed then, all other things being equal, a subsequent replacement of the top coat with water reed would be unlikely to result in a further material alteration to the historic character and the Inspector did not believe such a condition would be capable of being enforced or, even if it were, that its application would be reasonable.

Considerable weight and importance is attached to the harm to the significance of the heritage asset although this would not lead to the loss of the listed building or the removal of the thatched roof. As this is one thatched dwelling within a much larger Conservation Area containing a number of such properties the resulting harm would be less than substantial. When weighed against NPPF paragraph 134 regarding public benefits and the securing the optimum viable use; the main public benefits resulting from the scheme would be the contribution made from retaining thatch on the building; environmental benefits from the replacement of the existing top coat (including an improvement to the appearance of the building and the Conservation Area); and some economic and social benefits, in supporting and sustaining the thatching industry, including in the production of materials and the continued development of appropriate methods and techniques. As similar benefits would also arise from the use of combed wheat they were only accorded moderate weight as were suggestions that empirical evidence on the performance of water reed in comparison to combed wheat reed might also be obtained.

It was not considered likely (given the location and quality of the building), that its viable use as a dwelling would be at risk should the appeal fail.

Given the great weight that Paragraph 132 of the NPPF gives to the conservation of a heritage asset in considering the impact of a proposal on its significance a clear and convincing justification has not been demonstrated and, whilst the use of water reed may be viable, it would not represent its optimum use.

Other related cases cited :

Related appeal decisions Ref: APP/W0530/F/07/2061491 and APP/W0530/E/07/2058504 (not replicated here) were cited but only in relation to main ridge and the dormer ridges, and relevant national and local policies. Changes in thatching material were allowed by appeal decisions Ref: APP/B1225/E/12/2187662 and APP/Y3940/E/13/2207654 but both dealt with changes from wheat reed to water reed on buildings in other parts of the country and were not relevant to the case in hand.

Conclusion

As heritage assets are irreplaceable the proposed works to the listed building would cause great harm to the significance, but in the terms of the National Planning Policy Framework (Framework) that harm would be less than substantial. The building was already in optimum viable use as a dwelling and there were insufficient public benefits outweigh that harm. Whilst the need for repair and maintenance of the thatch was understood, insufficient clear and convincing justification has been made for the proposals. It was put to me to explain why the proposed works would be necessary to preserve the heritage asset. The proposal would fail to preserve the special architectural interest of the listed building and its long straw thatched roof which is a feature of special interest; be contrary to the NPPF and contrary to the advice in the SPG. This is a compelling objection to the scheme - is sufficient to dismiss the appeal.

Conservation Area considerations

Within the Great Horwood Conservation Area the listed building makes a positive contribution to the attractive semi-rural appearance close by and because it is the only long straw thatched building in the village it is important to the historic character of the Conservation Area, which it is desirable to preserve. Although there would be little visible difference between the types of thatch proposed, the authenticity and integrity of the long straw thatched roof would be harmfully diminished and not outweighed by public benefits. As such the character of the Conservation Area would fail to be preserved.

EXEMPLAR Appeal Upheld

CASE 3

‘The works proposed are to remove the existing thatch and parts of the roof structure to half the existing roof, re-timber (to structural engineers detail) and re-thatch up to central chimney stack’ Appeal upheld 15 April 2013. Appeal Ref: APP/B1225/E/12/2187662. St Nicholas Cottage, Chaldon Herring, Dorset DT2 8DN. Purbeck District Council.

Main Issue

The effect of this choice of thatching material on the significance; and the setting within the Conservation Area, given that consent had previously granted for the replacement of some roof timbers and re-thatching in wheat reed (or straw). Now the proposal was for replacement of the same timbers, but with re-thatching in water reed.

Summary

Development Plan policies were not directly relevant but special regard under Section 16(2) of the 1990 Act was significant as was Section 72(1) of the same Act. PPS5 has been cited but at the time of the appeal had been superseded the policies in the NPPF which were very similar and the intent was the same.

The need to replace roof timbers had previously been granted approval, occasioning the total loss of the existing thatch. Notwithstanding the ‘consumable’ nature of thatch, this was historic fabric and its loss would cause substantial harm under NPPF paragraph 133. That harm would have been balanced by the public benefits of the continuing conservation of the building and based on the use of wheat reed as a replacement material. A new balancing exercise was now required regarding the revise use of water reed, the material used by a high proportion of thatched buildings in the village.

Water reed had been permitted nearby in response to an urgent need to secure the wellbeing of the building and demonstrated the Council’s willingness to consider the circumstances of individual cases and make decisions in the best interest of the listed building. This was not, as asserted, the same as being inconsistent showed appropriate flexibility.

The casual observer, or even some experts, might have difficulty in determining the visual difference between wheat reed and water reed, and appearance was an aspect of the conservation area that Section 72(1) of the Act seeks to preserve. The preservation of listed buildings however goes beyond the immediately obvious or even the visible. The historic significance may be buried within fabric and only emerge during repair work, but due to being part of the historic significance, was as worthy of control as more readily appreciated aspects.

It was agreed that historically, thatching materials would have been obtained from whatever sources were available at the time and within a reasonable proximity to the site. Water reed had evidently been grown locally and wheat reed must have been too. The relative merits of the former over the latter: longevity, ease of working and so forth, had been debated and these matters carried some weight but they would not generally outweigh the desirability of making use of the same material as had been used on any particular building when carrying out repairs or spar-coating, in order to preserve the significance.

Nevertheless, in this case the original material was being removed wholesale, and the current condition of the thatch on St Nicholas Cottage detracted from the appearance of the listed building and conservation area. If slippage of the thatch, opening-up of voids and general degradation were not addressed promptly there appeared to be a real and serious threat to the building leading to damage to other features of significance.

The need to carry out work the work urgently has coincided with a well-documented shortage of wheat reed due to the weather of the last few years (seed for the coming year’s crop has not been drilled due to poor ground conditions) and as a potentially transitory situation and did not warrant this the need for policy change or change of approach in principle. However, because of the particular urgency of this case, the balance lies in permitting the use of a readily available material with the object of securing the prompt re-thatching in the coming summer. A condition requiring a one year period for the commencement of the works was therefore agreed.

Conclusion

Whilst the loss of thatching material causes substantial harm, the public benefits of ensuring the continued preservation of the listed building and limiting further losses are sufficiently substantial as to outweigh that harm as required by paragraph 133 of the NPPF. The enhancement to the character and appearance of the conservation area over the existing position, albeit being largely common to both materials, adds weight to this view. On balance use of water reed would satisfy the statutory tests in the 1990 Act and would be in line with the aims of the statutory guidance, which makes provision for flexibility to address the needs of individual buildings at the time that work is required.

In this case, whilst the use of water reed is not preferred in view of the historic use of wheat reed, its use is justified in the interest of the timely preservation of the building and the character and appearance of its conservation area setting.

Appendix B

Some appeal summaries pre-dating the introduction of the NPPF

(These are case resumés and readers should also direct themselves to the full decision letter.)

CASE 3

‘The works proposed are change of thatch material combed wheat to water reed, re-thatch’ Appeal dismissed. Appeal Ref: APP/R3325/E/04/1148702 Magdalen Cottage, Stoney Lane, Stocklinch TA19 9JH. South Somerset District Council.

Main Issue

Whether the use of water reed in place of combed wheat reed would adversely affect the character of the building.

Summary

The building, a detached cottage was listed Grade 2 in June 1972 and was probably of fifteenth century origin. Some restoration appeared to have taken place in the early 1970s including construction of a new thatched roof above two cruck trusses and insertion of dormer windows on the rear elevation. Consent for renewal of the thatch in water reed in 1988 had been refused there had been further deterioration since, particularly the ridge, showing signs of water penetration. It was proposed to retain the combed wheat base but add a top coat in water reed.

Examples of both materials were evident in the vicinity with some roofs employing both materials on different slopes. The Council contended that combed wheat read was the predominant traditional material in this part of Somerset and use of water reed seemed a relatively recent development. This was due in part to a decline in local availability of the wheat reed.

While a casual observer might see little difference between the two materials, differences in texture and detailing would be evident on closer inspection. The advice in PPG15 Annex C paragraph C29 was invoked, with more recent reinforcement from English Heritage guidance, particularly that character stems from both the material and the style of thatching employed.

The appellant wished to use water reed because of greater longevity (and had reroofed twice in the preceding 30 years). The Inspector noted that if this were so, it would be more sustainable by using fewer natural resources, but research still in progress on the longevity of the two materials has not been completed and therefore no conclusions could be drawn.

Differences in appearance might be reduced if water reed were laid in a style to resemble combed wheat reed as closely as possible but as the final appearance contributed to the character of the building it had retained since it had been listed, a change of material would therefore be harmful to that character.

A change to water reed would not be consistent with local thatching tradition in the locality and by not being available locally would have to be brought in from elsewhere making it an alien and inappropriate material. Refusal to allow it might help foster production of combed wheat reed in the area and sustain a local tradition. Although there was sympathy for the appellant’s case, this was not sufficient to justify a proposed change of material.

Structure Plan and Local Plan policies although not directly relevant to an application for listed building consent, supported the Council’s decision in this case.

Conclusion

Water reed as a thatching material, in place of combed wheat reed, would adversely affect the character of the listed building and the appeal was therefore dismissed.




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