[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-seo-664413-105":3,"detail-sidebar-cat-0-en-105":80,"doc-detail-664413-en":130},{"code":4,"msg":5,"data":6},0,"ok",{"site_id":7,"language":8,"slug":9,"title":10,"keywords":11,"description":12,"schema_data":13,"social_meta":73,"head_meta":75,"extra_data":77,"updated_unix":79},105,"en","insulating-thatched-roofs-guidance-note","Insulating Thatched Roofs - Guidance Note","","Guidance note focused on insulating thatched roofs, outlining core principles, technical risks, appropriate materials, and practical methods. It explains the heritage and performance assessment needed before any thermal upgrading, emphasizing that many historic thatched buildings already meet thermal needs. The guidance discusses condensation and interstitial condensation risks, impacts on mould and occupant health, and material choices such as hygroscopic insulation, ventilation, and vapour control strategies, stressing careful, case-by-case decisions.",{"@graph":14,"@context":72},[15,34,55],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/research-report/","Research & Report",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/document/insulating-thatched-roofs-guidance-note/664413/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/insulating-thatched-roofs-guidance-note/664413.png","ImageObject",300,407,{"name":42,"@type":43},"awa","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-10-30","2026-10-29",true,{"@type":52,"interactionType":53,"userInteractionCount":30},"InteractionCounter",{"@type":54},"ViewAction",{"@type":56,"mainEntity":57},"FAQPage",[58,64,68],{"name":59,"@type":60,"acceptedAnswer":61},"Why should insulation changes to thatched roofs be attempted only when really necessary?","Question",{"text":62,"@type":63},"Many thatched buildings already provide adequate thermal performance. Improvements should not compromise the traditional breathable performance of the building.","Answer",{"name":65,"@type":60,"acceptedAnswer":66},"What is the main technical risk when upgrading the thermal performance of older buildings?",{"text":67,"@type":63},"The most significant risk is condensation, including surface condensation and interstitial condensation between layers, which can lead to mould, health problems, and material decay.",{"name":69,"@type":60,"acceptedAnswer":70},"How can advice address condensation risk when adding insulation in existing permeable construction?",{"text":71,"@type":63},"The guidance generally uses hygroscopic insulation to buffer temperature and vapour pressure fluctuations, lowering condensation risk, while still requiring careful management of humidity, ventilation, and vapour control layers.","https://schema.org",{"og:url":32,"og:type":74,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":76,"canonical":32},"index,follow",{"doc_id":78,"site_id":7},664413,1793254321,{"code":4,"msg":81,"data":82},"success",[83,87,91,95,100,105,110,114,119,122,126],{"id":22,"doc_module":4,"doc_module_name":25,"category_name":84,"show_sort_weight":85,"slug":86},"Story & Novel",90,"story-novel",{"id":26,"doc_module":4,"doc_module_name":25,"category_name":88,"show_sort_weight":89,"slug":90},"Literature",80,"literature",{"id":33,"doc_module":4,"doc_module_name":25,"category_name":92,"show_sort_weight":93,"slug":94},"Exam",70,"exam",{"id":96,"doc_module":4,"doc_module_name":25,"category_name":97,"show_sort_weight":98,"slug":99},5,"Comic",60,"comic",{"id":101,"doc_module":4,"doc_module_name":25,"category_name":102,"show_sort_weight":103,"slug":104},6,"Technology",50,"technology",{"id":106,"doc_module":4,"doc_module_name":25,"category_name":107,"show_sort_weight":108,"slug":109},7,"Healthcare",40,"healthcare",{"id":111,"doc_module":4,"doc_module_name":25,"category_name":29,"show_sort_weight":112,"slug":113},8,30,"research-report",{"id":115,"doc_module":4,"doc_module_name":25,"category_name":116,"show_sort_weight":117,"slug":118},9,"Religion & Spirituality",20,"religion-spirituality",{"id":117,"doc_module":4,"doc_module_name":25,"category_name":120,"show_sort_weight":117,"slug":121},"World Cup","world-cup",{"id":123,"doc_module":4,"doc_module_name":25,"category_name":124,"show_sort_weight":123,"slug":125},10,"Lifestyle","lifestyle",{"id":127,"doc_module":4,"doc_module_name":25,"category_name":128,"show_sort_weight":96,"slug":129},19,"General","general",{"code":4,"msg":81,"data":131},{"doc_id":78,"user_id":132,"nickname":42,"user_avatar":133,"doc_module":4,"category_id":111,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":30,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":139,"language":140,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":141,"faqs":142,"seo_title":143,"seo_description":12,"update_tm":79,"read_time":144},3985747858093,"https://ap-avatar.wpscdn.com/davatar_3d24733baf745e90a7e4bdd5f77d97b2","Energy Efficiency and Historic Buildings  \nInsulating Thatched Roofs  \nThis guidance note has been prepared and edited by David Pickles. It forms one of a series of thirteen guidance notes covering the thermal upgrading of building elements such as roofs, walls and floors.  \nFirst published by English Heritage March 2012.  \nThis edition (v1 . 1) published by Historic England April 2016.  \nAll images © Historic England unless otherwise stated.  \nIllustrations drawn by Simon Revill.  \nOur full range of guidance on energy efficiency can be found at:  \n[HistoricEngland.org.uk/energyefficiency](HistoricEngland.org.uk/energyefficiency)  \nFront cover:  \nThatch repairs in progress .© Philip White .  \nSummary  \nThis guidance provides advice on the principles, risks, materials and methods for insulating thatched roofs. There are estimated to be about fifty thousand thatched buildings in England today, some of which retain thatch which is over six hundred years old. Thatching reflects strong vernacular traditions all over the country.  \nWell-maintained thatch is a highly effective weatherproof coating as traditional deep thatched eaves will shed rainwater without the need for any down pipes or gutters. Locally grown thatch is a sustainable material, which has little impact on the environment throughout its life-cycle. It requires no chemicals to grow, can be harvested by hand or using traditional farm machinery, requires no mechanical processing and therefore has low embodied energy and can be fixed using hand tools. At the end of its life it can be composted and returned to the land.  \nThatch has a much greater insulating value than any other traditional roof covering. With the right choice of material and detailing, a well-maintained thatched roof will keep a building warm in winter and cool in summer and has the added advantage of being highly sound-proof.  \nThe guidance stresses that changes to improve the energy performance of thatched roofs should only be attempted where really necessary as many thatched buildings already provide adequate thermal performance and where the traditional ‘breathable’performance of the building will not be compromised.  \nContents  \nIntroduction.........................................1 3 Thatched Roofs as Warm Roofs ....9  \nEnergy Planning ....................................................... 1 3.1 Adding insulation from above .................. 11  \nTechnical Risks......................................................... 1 3.2 Adding insulation below the rafters ......... 12  \nTechnical Details ...................................................... 2  \n4 Thatched Roofs as Cold Roofs .... 14  \n1 Thatched Roof Construction ........3  \n1.1 Thatch covering ...........................................3 5 Where to Get Advice................... 16  \n1.3 Roof structure .............................................. 6  \n1.4 Internal finishes to thatched roofs ............. 6 5.1 Contact Historic England .......................... 17  \n2 Energy Efficiency Measures .........7  \n2.1 Thermal properties of thatched roofs .............................................. 7  \n2.2 Cold roof or warm roof? ..............................8  \nIntroduction  \nEnergy Planning  \nBefore contemplating measures to enhance the thermal performance of a historic building it is important to assess the building and the way it is used in order to understand:  \n􀂄 the heritage values (significance) of the building  \n􀂄 the construction and condition of the building fabric and building services  \n􀂄 the existing hygrothermal behaviour of the building  \n􀂄 the likely effectiveness and value for money of measures to improve energy performance  \n􀂄 the impact of the measures on significance  \n􀂄 the technical risks associated with the measures  \nThis will help to identify the measures best suited to an individual building or household, taking behaviour into consideration as well as the building envelope and services .  \nTechnical Risks  \nAltering th","cbCaib0EzSUnbLmG","https://ap.wps.com/l/cbCaib0EzSUnbLmG","pdf",1032028,22,"English","# Summary\n# Introduction\n## Energy Planning\n## Technical Risks\n# Technical Details\n## Thatched Roof Construction\n## Energy Efficiency Measures\n# Where to Get Advice","[{\"question\":\"Why should insulation changes to thatched roofs be attempted only when really necessary?\",\"answer\":\"Many thatched buildings already provide adequate thermal performance. Improvements should not compromise the traditional breathable performance of the building.\"},{\"question\":\"What is the main technical risk when upgrading the thermal performance of older buildings?\",\"answer\":\"The most significant risk is condensation, including surface condensation and interstitial condensation between layers, which can lead to mould, health problems, and material decay.\"},{\"question\":\"How can advice address condensation risk when adding insulation in existing permeable construction?\",\"answer\":\"The guidance generally uses hygroscopic insulation to buffer temperature and vapour pressure fluctuations, lowering condensation risk, while still requiring careful management of humidity, ventilation, and vapour control layers.\"}]","Insulating Thatched Roofs - Guidance Note | PDF",55]