{"title":"VCL Membrane (Vapour Control Layer)","description":"\u003cp\u003eA vapour control layer you paint on. \u003ca href=\"\/en-la\/products\/passive-purple-internal-airtight-vapour-control-paint-11-4kg\"\u003ePassive Purple\u003c\/a\u003e and \u003ca href=\"\/en-la\/products\/airtight-white-membrane-paint\"\u003eAirtight White\u003c\/a\u003e form a continuous liquid VCL membrane across walls, ceilings and floors — tested to both ASTM and EN standards, with Passive Purple Passivhaus certified and BBA approved. Spray, roller or brush applied over blockwork, OSB and plasterboard, with Retrofit Airtightness paints for upgrade work and Passivhaus Airtight Sealant for junctions and penetrations. One wet coat gives you vapour control and airtightness in a single layer, working alongside tapes and sealants as a complete airtight system.\u003c\/p\u003e","products":[{"product_id":"airtight-white-membrane-paint","title":"Airtight White - Vapour Control, Airtight \u0026 Smoke Tight Paint (11.4kg) - Spray \/ Roller Applied","description":"\u003ch2 data-start=\"93\" data-end=\"127\"\u003ePassive Purple Airtight White\u003c\/h2\u003e\n\u003cp data-start=\"128\" data-end=\"180\"\u003e\u003cstrong data-start=\"128\" data-end=\"180\"\u003eVOC-Free Airtight, Vapour \u0026amp; Gas Control Membrane\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"182\" data-end=\"389\"\u003ePassive Purple Airtight White is a \u003cstrong data-start=\"217\" data-end=\"260\"\u003eVOC-free, water-based airtight membrane\u003c\/strong\u003e providing reliable \u003cstrong data-start=\"280\" data-end=\"298\"\u003evapour control\u003c\/strong\u003e and protection against \u003cstrong data-start=\"322\" data-end=\"349\"\u003eradon and methane gases, \u003c\/strong\u003ewithout any nasty chemicals or fumes.\u003c\/p\u003e\n\u003cp data-start=\"391\" data-end=\"687\"\u003eIdeal for those on-site “oops” moments, it can be applied directly onto \u003cstrong data-start=\"463\" data-end=\"479\"\u003eplasterboard\u003c\/strong\u003e if a vapour control layer has been missed. When used with \u003cstrong data-start=\"538\" data-end=\"551\"\u003eIM Primer\u003c\/strong\u003e, it can be \u003cstrong data-start=\"563\" data-end=\"595\"\u003eleft on show or painted over\u003c\/strong\u003e, making it perfect for exposed environments such as \u003cstrong data-start=\"648\" data-end=\"686\"\u003ecar parks, museums, and stairwells\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp data-start=\"689\" data-end=\"910\"\u003eOnce dry, it forms a \u003cstrong data-start=\"710\" data-end=\"749\"\u003etough yet flexible polymer membrane\u003c\/strong\u003e that moves with the building and resists impact damage, eliminating the rips, tears, staple holes and failed tapes associated with traditional paper membranes.\u003c\/p\u003e\n\u003cp data-start=\"912\" data-end=\"954\" data-is-last-node=\"\" data-is-only-node=\"\"\u003eLess labour. Less waste. More performance.\u003c\/p\u003e\n\u003cp data-start=\"912\" data-end=\"954\" data-is-last-node=\"\" data-is-only-node=\"\"\u003eCheck out our \u003ca href=\"https:\/\/intelligentmembranes.aflip.in\/80f3ef4f93.html\" title=\"Retrofit Vapour control\" rel=\"noopener\" target=\"_blank\"\u003ecase study \u003c\/a\u003e\u003c\/p\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eLeft on show - see it in 360°\u003c\/h2\u003e\n\u003cp\u003eA museum project where Airtight White is doing both jobs at once: the airtightness and vapour control layer on the concrete panel walls, and the finished surface that stays on view.\u003c\/p\u003e\n\u003cfigure style=\"margin: 20px 0; padding: 0;\"\u003e\n\u003cdiv style=\"position: relative; padding-top: 56.25%; background: #f4f4f4; border-radius: 6px; overflow: hidden;\"\u003e\u003ciframe src=\"https:\/\/kuula.co\/share\/LnD57?logo=1\u0026amp;info=1\u0026amp;fs=1\u0026amp;vr=0\u0026amp;zoom=1\u0026amp;sd=1\u0026amp;thumbs=1\" title=\"Airtight White left on show as the finished surface, museum project — 360 degree site tour\" loading=\"lazy\" style=\"position: absolute; top: 0; left: 0; width: 100%; height: 100%; border: 0;\"\u003e\u003c\/iframe\u003e\u003c\/div\u003e\n\u003cfigcaption style=\"margin-top: 10px; font-size: 0.9rem;\"\u003eClick and drag to look around. \u003ca href=\"\/en-la\/pages\/360-images\"\u003eSee all our 360° site tours\u003c\/a\u003e.\u003c\/figcaption\u003e\n\u003c\/figure\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eTest data - worldwide\u003c\/h2\u003e\n\u003cp\u003eAirtight White is the white-pigmented version of Passive Purple - the same liquid airtight membrane formulation. Passive Purple has been independently tested to \u003cstrong\u003eboth ASTM and EN standards\u003c\/strong\u003e, so it can be specified worldwide:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFrench A+ indoor-air rating \u0026amp; Finnish M1 class\u003c\/strong\u003e - very low VOC emissions (EN 16516 \/ RTS)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePassive House Institute Class A airtight\u003c\/strong\u003e - 0.02 m³\/h·m² @ 50 Pa (EN 12114)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAir barrier material\u003c\/strong\u003e - 0.02 L\/s·m² at 75 Pa (ASTM E2178)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReaction to fire\u003c\/strong\u003e - Class A to ASTM E84 (Flame Spread 0); Euroclass C-s1,d0 to EN 13501-1 (B-s1,d0 with FRED)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWatertight\u003c\/strong\u003e (EN 14891) \u0026amp; intelligent vapour control, Sd ~0.8–40 m (EN ISO 12572)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh solar reflectance\u003c\/strong\u003e - the white finish reflects even more solar energy (the purple grade is independently rated SRI 52, ASTM E1980)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRadon barrier\u003c\/strong\u003e - diffusion coefficient 3.3 × 10⁻¹² m²\/s (ISO\/TS 11665-13)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMethane \/ ground-gas barrier\u003c\/strong\u003e - low permeability (ISO 15105)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStrong adhesion\u003c\/strong\u003e - steel 2.7, CLT 1.83, gypsum 1.6, brick 1.5 N\/mm² (EN ISO 4624)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlexible \u0026amp; crack-bridging\u003c\/strong\u003e - ~219–350% elongation (EN 12311-1)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e10\/10 mould resistance\u003c\/strong\u003e - no defacement (ASTM D3273)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEnvironmental Product Declaration\u003c\/strong\u003e (EN 15804)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCertificates\u003c\/strong\u003e - Passivhaus certification and BBA approval are held by Passive Purple, not by Airtight White\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Passive Purple \u0026amp; Airtight White Tested \u0026amp; Certified\"\u003eSee all test data \u0026amp; certifications →\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eHelpful guides related to this product:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Tested \u0026amp; Certified\"\u003ePassive Purple \u0026amp; Airtight White: Tested \u0026amp; Certified (ASTM \u0026amp; EN data)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/passive-purple-french-a-plus-emissions-rating\" title=\"French A+ rating\"\u003eThe French A+ indoor-air rating explained\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/what-is-a-vapour-control-layer-vcl-explained\" title=\"What Is a Vapour Control Layer? | VCL Explained\"\u003eWhat Is a Vapour Control Layer? | VCL Explained\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/builder-forgot-the-vapour-control-layer-how-to-fix-it\" title=\"My Builder Forgot the Vapour Control Layer? Here’s How to Fix It\"\u003eMy Builder Forgot the Vapour Control Layer? Here’s How to Fix It\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/case-study\/reuben-college-oxford-award-winning-airtight-basement-solution-using-airtight-white\" title=\"Reuben College, Oxford\"\u003eReuben College, Oxford – Award-Winning Airtight Basement with Airtight White\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eQuality assurance:\u003c\/strong\u003e \u003ca href=\"\/en-la\/pages\/qa-sign-off-downloads\"\u003eDownload the free Installation \u0026amp; QA Record sign-off sheet (IM-QA-03)\u003c\/a\u003e for this product.\u003c\/p\u003e","brand":"Intelligent Membranes","offers":[{"title":"Default Title","offer_id":52608799965524,"sku":"IM\/00ATW11.4","price":99.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Airtight_White_2.png?v=1792499467"},{"product_id":"white-airtight-vapour-control-paint-6-9kg","title":"Airtight White Brush - Home Pack (6.9kg) - Vapour Control Paint - Brush Applied","description":"\u003cp\u003e\u003cstrong\u003ePassive Purple Airtight White Brush\u003c\/strong\u003e is a \u003cstrong\u003efibre-reinforced polymer emulsion\u003c\/strong\u003e applied by paintbrush to create a \u003cstrong\u003epermanent liquid airtight vapour control membrane\u003c\/strong\u003e. Its smooth white finish makes it perfect for \u003cstrong\u003eretrofits, detailing, and projects where the airtight layer is left exposed\u003c\/strong\u003e.\u003c\/p\u003e\n\u003ch2\u003eKey Features \u0026amp; Benefits\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePassive Purple formulation\u003c\/strong\u003e – the same formulation as BBA-approved, Passivhaus-certified Passive Purple\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eM1 Class, VOC-Free\u003c\/strong\u003e – water-based, non-toxic, and safe for installers and the environment\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFire Class C Rated\u003c\/strong\u003e – safer than traditional membranes rated only Class E\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUniversal Adhesion\u003c\/strong\u003e – bonds to concrete, brick, timber, plasterboard, OSB, steel, and more\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCoverage Efficiency\u003c\/strong\u003e – \u003cstrong\u003e1kg covers 1m²\u003c\/strong\u003e; one operative can apply up to \u003cstrong\u003e300m² per day\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWhere to Use Airtight White Brush\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eFloor, wall, and ceiling junctions\u003c\/li\u003e\n\u003cli\u003eWindow and door reveals\u003c\/li\u003e\n\u003cli\u003eService penetrations (pipes, ducts, cables)\u003c\/li\u003e\n\u003cli\u003eSmall retrofit airtightness projects\u003c\/li\u003e\n\u003cli\u003eAny area where a \u003cstrong\u003ewhite airtight coating is required on show\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe \u003cstrong\u003e6.9kg Passive Purple Airtight White Brush\u003c\/strong\u003e is the \u003cstrong\u003efast, proven solution\u003c\/strong\u003e for creating airtight, durable, and visually clean airtight layers in both new builds and retrofit projects.\u003c\/p\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eTest data - worldwide\u003c\/h2\u003e\n\u003cp\u003eAirtight White Brush is the white-pigmented Passive Purple formulation. Passive Purple has been independently tested to \u003cstrong\u003eboth ASTM and EN standards\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFrench A+ indoor-air rating \u0026amp; Finnish M1 class\u003c\/strong\u003e - very low VOC emissions (EN 16516 \/ RTS)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePassive House Institute Class A airtight\u003c\/strong\u003e - 0.02 m³\/h·m² @ 50 Pa (EN 12114)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAir barrier material\u003c\/strong\u003e - 0.02 L\/s·m² at 75 Pa (ASTM E2178)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReaction to fire\u003c\/strong\u003e - Class A to ASTM E84; Euroclass C-s1,d0 to EN 13501-1 (B-s1,d0 with FRED)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWatertight\u003c\/strong\u003e (EN 14891) \u0026amp; intelligent vapour control, Sd ~0.8–40 m (EN ISO 12572)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStrong adhesion\u003c\/strong\u003e - steel 2.7, CLT 1.83, gypsum 1.6, brick 1.5 N\/mm² (EN ISO 4624)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e10\/10 mould resistance\u003c\/strong\u003e (ASTM D3273) · 🛡️ radon \u0026amp; methane barrier · ♻️ EPD (EN 15804)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCertificates\u003c\/strong\u003e - Passivhaus certification and BBA approval are held by Passive Purple, not by Airtight White Brush\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Passive Purple Tested \u0026amp; Certified\"\u003eSee all test data \u0026amp; certifications →\u003c\/a\u003e · \u003ca href=\"\/en-la\/blogs\/educational\/passive-purple-french-a-plus-emissions-rating\"\u003ethe French A+ rating explained\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eHelpful guides related to this product:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/what-is-a-vapour-control-layer-vcl-explained\" title=\"What Is a Vapour Control Layer? | VCL Explained\"\u003eWhat Is a Vapour Control Layer? | VCL Explained\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/builder-forgot-the-vapour-control-layer-how-to-fix-it\" title=\"My Builder Forgot the Vapour Control Layer? Here’s How to Fix It\"\u003eMy Builder Forgot the Vapour Control Layer? Here’s How to Fix It\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/how-to-retrofit-vapour-control-without-the-mess-bba-approved-passivhaus-certified-building-control-ready\" title=\"How to Retrofit Vapour Control Without the Mess\"\u003eHow to Retrofit Vapour Control Without the Mess\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eQuality assurance:\u003c\/strong\u003e \u003ca href=\"\/en-la\/pages\/qa-sign-off-downloads\"\u003eDownload the free Installation \u0026amp; QA Record sign-off sheet (IM-QA-04)\u003c\/a\u003e for this product.\u003c\/p\u003e","brand":"Intelligent Membranes","offers":[{"title":"Default Title","offer_id":52608800129364,"sku":"IM\/00ATWB6.9","price":59.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Airtight_White_Brush.png?v=1792499655"},{"product_id":"passive-purple-internal-airtight-vapour-control-paint-11-4kg","title":"Passive Purple - Vapour Control, Airtight \u0026 Smoke Tight Paint (11.4kg) - Spray \/ Roller Applied","description":"\u003cp\u003e\u003cpicture\u003e\u003csource media=\"(max-width:749px)\" srcset=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/new_passive_purple_product_hero_mobile_2.png?v=1784621723\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/new_passive_purple_product_hero_desktop_1.png?v=1784621723\" alt=\"Passive Purple liquid-applied airtight, vapour control and smoke tight membrane — Passivhaus certified, BBA approved and tested to ASTM and EN standards\" loading=\"eager\" style=\"width: 100%; height: auto; display: block; border-radius: 10px; margin: 0 0 24px;\"\u003e\u003c\/picture\u003e\u003c\/p\u003e\n\u003ch2\u003eWhat is Passive Purple and How Does it Work?\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePassive Purple\u003c\/strong\u003e is the world’s first \u003cstrong\u003ePassivhaus-certified liquid vapour control, airtight, and smoke-tight paint\u003c\/strong\u003e - a high-performance vapour-control membrane that creates a \u003cstrong\u003econtinuous vapour control, airtight, and smoke-tight layer\u003c\/strong\u003e across the building envelope. Unlike tapes, foils, or traditional membranes, Passive Purple is \u003cstrong\u003espray or roller-applied\u003c\/strong\u003e, forming a seamless coating that seals even the most complex details.\u003c\/p\u003e\n\u003cp\u003eApplied to the \u003cstrong\u003ewarm side of insulation\u003c\/strong\u003e, Passive Purple prevents unwanted air leakage through walls, floors, roofs, and junctions. It is suitable for both \u003cstrong\u003enew builds\u003c\/strong\u003e and \u003cstrong\u003eretrofit airtightness projects\u003c\/strong\u003e, helping achieve strict UK airtightness standards and Passivhaus performance levels.\u003c\/p\u003e\n\u003ch2\u003eWhy Liquid Airtight Paint?\u003c\/h2\u003e\n\u003cp\u003eAir leakage is one of the biggest causes of \u003cstrong\u003eheat loss, condensation, and mould\u003c\/strong\u003e in buildings. Different materials such as brick, timber, steel, and concrete expand and contract at different rates, creating micro-cracks in plaster and finishing layers. These cracks become hidden leakage points that compromise airtightness tests and waste energy.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eLiquid airtight paint solves this problem.\u003c\/strong\u003e By coating surfaces with Passive Purple, you achieve a \u003cstrong\u003eflexible, durable airtight layer\u003c\/strong\u003e that adapts to movement in the building fabric, ensuring long-term protection against draughts and damp.\u003c\/p\u003e\n\u003ch2\u003eSpray \/ Roller or Brush Application\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpray application:\u003c\/strong\u003e Using an airless machine or roller, one installer can apply up to \u003cstrong\u003e300 m² per day\u003c\/strong\u003e, making it one of the fastest airtightness solutions available.\u003c\/li\u003e\n\u003cli\u003e\n\u003ca rel=\"noopener\" title=\"paint on airtight vapour control\" href=\"https:\/\/intelligentmembranes.com\/products\/passive-purple-internal-airtight-vapour-control-paint-6-9\" target=\"_blank\"\u003e\u003cstrong\u003eBrush application (Passive Purple Brush)\u003c\/strong\u003e\u003c\/a\u003e - A fibre-reinforced version, ideal for sealing junctions, penetrations, cracks (2- 5 mm), and smaller projects such as houses and retrofits\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eTogether, the spray and brush systems create a \u003cstrong\u003ecomplete airtight solution\u003c\/strong\u003e – from large surface areas to the smallest details.\u003c\/p\u003e\n\u003ch2\u003eSuitability of Passive Purple\u003c\/h2\u003e\n\u003cp\u003ePassive Purple is suitable for all types of building construction - New builds, Retrofits, Traditional build, Light Gauge Steel (LGS)\u003c\/p\u003e\n\u003ch2\u003eThe Benefits of Passive Purple\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e✅ \u003cstrong\u003ePassivhaus certified\u003c\/strong\u003e for guaranteed performance\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003eSeamless and flexible\u003c\/strong\u003e – no weak points or overlaps\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003eRetrofit-ready\u003c\/strong\u003e – apply internally without removing walls\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003eWater-based and low VOC\u003c\/strong\u003e, safe for indoor use\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003eWorks on all substrates\u003c\/strong\u003e – brick, block, timber, concrete, plasterboard, OSB, and steel\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003ePermanent airtight layer\u003c\/strong\u003e – can be plastered, rendered, or painted once cured\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eAirtightness, Explained\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat is airtightness?\u003c\/strong\u003e Controlling unintended air leakage through the building fabric.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHow do you achieve airtightness?\u003c\/strong\u003e By creating a continuous airtight barrier, best achieved with liquid airtight membranes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat are the airtightness standards in the UK?\u003c\/strong\u003e New builds must achieve ≤10 m³\/h·m² @ 50 Pa, while Passivhaus requires ≤0.6 ACH.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhy does airtightness matter?\u003c\/strong\u003e It reduces energy loss, improves comfort, prevents condensation, and supports a healthy indoor climate.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003ePassive Purple and Passivhaus\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat is Passivhaus?\u003c\/strong\u003e A building standard focused on extreme energy efficiency and occupant comfort. \u003ca href=\"https:\/\/intelligentmembranes.com\/pages\/360-images\" title=\"360 images of liquid applied airtight vapour control\" rel=\"noopener\" target=\"_blank\"\u003eCheck out the 360 images \u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe five principles of Passivhaus:\u003c\/strong\u003e Airtightness, insulation, high-performance glazing, thermal bridge-free design, and ventilation with heat recovery.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCan it go on Retrofit Projects?\u003c\/strong\u003e Yes, it can; \u003ca rel=\"noopener\" title=\"Retrofit airtightness\" href=\"https:\/\/intelligentmembranes.com\/blogs\/case-study\/airtight-membranes-on-brickwork-seamless-retrofit-sealing-with-passive-purple\" target=\"_blank\"\u003echeck out the case studies \u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003ca rel=\"noopener\" title=\"examples of smoke tight and airtight liquid vapour controls\" href=\"https:\/\/intelligentmembranes.com\/pages\/blogs\" target=\"_blank\"\u003eExamples of Passivhaus projects\u003c\/a\u003e:\u003c\/strong\u003e Thousands across Europe and the UK now use liquid airtight membranes like Passive Purple to achieve certification.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003ePreparation \u0026amp; Priming\u003c\/h2\u003e\n\u003cp\u003eGreat airtightness starts with the right prep. On bare, dusty, porous or lime substrates, prime first with \u003ca href=\"\/en-la\/products\/lime-prime-10kg\" title=\"Lime Prime\"\u003eLime Prime\u003c\/a\u003e; on dense, sealed or older substrates that need consolidating, use \u003ca href=\"\/en-la\/products\/render-primer-im\" title=\"Primer I.M\"\u003ePrimer I.M\u003c\/a\u003e. Once Passive Purple has cured, prime it with \u003ca href=\"\/en-la\/products\/supergrip-primer-10kg\" title=\"Supergrip primer\"\u003eSupergrip\u003c\/a\u003e so plaster and dot-and-dab bond firmly. Right primer, reliable bond.\u003c\/p\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eTested \u0026amp; Certified - worldwide\u003c\/h2\u003e\n\u003cp\u003ePassive Purple is tested to \u003cstrong\u003eboth ASTM and EN standards\u003c\/strong\u003e, making it suitable for projects worldwide:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFrench A+ indoor-air rating \u0026amp; Finnish M1 class\u003c\/strong\u003e - very low VOC emissions (EN 16516 \/ RTS)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePassive House Institute Class A airtight\u003c\/strong\u003e - 0.02 m³\/h·m² @ 50 Pa (EN 12114)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAir barrier material\u003c\/strong\u003e - 0.02 L\/s·m² at 75 Pa (ASTM E2178)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReaction to fire\u003c\/strong\u003e - Class A to ASTM E84 (Flame Spread 0); Euroclass C-s1,d0 to EN 13501-1 (B-s1,d0 with FRED)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWatertight\u003c\/strong\u003e (EN 14891) \u0026amp; intelligent vapour control, Sd ~0.8–40 m (EN ISO 12572)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSolar Reflectance Index 52\u003c\/strong\u003e - reflects ~45% of solar energy (ASTM E1980)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRadon barrier\u003c\/strong\u003e - diffusion coefficient 3.3 × 10⁻¹² m²\/s (ISO\/TS 11665-13)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMethane \/ ground-gas barrier\u003c\/strong\u003e - low permeability (ISO 15105)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStrong adhesion\u003c\/strong\u003e - steel 2.7, CLT 1.83, gypsum 1.6, brick 1.5 N\/mm² (EN ISO 4624)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlexible \u0026amp; crack-bridging\u003c\/strong\u003e - ~219–350% elongation (EN 12311-1)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e10\/10 mould resistance\u003c\/strong\u003e - no defacement (ASTM D3273)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEnvironmental Product Declaration\u003c\/strong\u003e (EN 15804)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePassivhaus certified \u0026amp; BBA approved\u003c\/strong\u003e; tested to ASTM E2178 and ASTM E84\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Passive Purple Tested \u0026amp; Certified\"\u003eSee all test data \u0026amp; certifications →\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e🇺🇸 \u003cstrong\u003eUS projects:\u003c\/strong\u003e tested to ASTM standards for world markets - \u003ca href=\"\/en-la\/pages\/us-specifications\" title=\"US specifications in CSI MasterFormat\"\u003edownload the US specifications (CSI MasterFormat)\u003c\/a\u003e or order through \u003ca href=\"\/en-la\/pages\/chicago\" title=\"Passive Purple Chicago — distributed and installed by WickRight\"\u003eWickRight, our Chicago distribution \u0026amp; installation partner\u003c\/a\u003e.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eWant to understand airtightness and vapour control before you buy? These guides explain how Passive Purple is used on real projects:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Passive Purple Tested \u0026amp; Certified\"\u003ePassive Purple: Tested \u0026amp; Certified (ASTM \u0026amp; EN data)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/passive-purple-class-a-airtight-passive-house-institute\" title=\"Passive House Class A airtight\"\u003ePassive House Institute Class A airtight (EN 12114)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/passive-purple-french-a-plus-emissions-rating\" title=\"French A+ rating\"\u003ePassive Purple: the French A+ indoor-air rating\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/pages\/liquid-airtight-membranes-vs-parge-coating\" title=\"Liquid Airtight Membranes vs Parge Coating\"\u003eLiquid Airtight Membranes vs Parge Coating\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/what-is-a-vapour-control-layer-vcl-explained\" title=\"What Is a Vapour Control Layer? VCL Explained\"\u003eWhat Is a Vapour Control Layer? | VCL Explained\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eQuality assurance:\u003c\/strong\u003e \u003ca href=\"\/en-la\/pages\/qa-sign-off-downloads\"\u003eDownload the free Installation \u0026amp; QA Record sign-off sheet (IM-QA-01)\u003c\/a\u003e for this product.\u003c\/p\u003e\n\u003ch2\u003eConnect the membrane at windows and junctions\u003c\/h2\u003e\n\u003cp\u003ePlan the adjoining tape detail as well as the coated area. Our \u003ca href=\"\/en-la\/blogs\/educational\/airtightness-tape-guide\"\u003eairtightness tape guide\u003c\/a\u003e covers width and substrate selection, while \u003ca href=\"\/en-la\/blogs\/educational\/airtightness-tape-vs-liquid-airtight-membrane\"\u003etape versus liquid membrane\u003c\/a\u003e explains compatible interfaces, preparation and inspection. Use the specified coating-to-tape detail and check continuity before covering.\u003c\/p\u003e","brand":"Intelligent Membranes","offers":[{"title":"Default Title","offer_id":52608801341780,"sku":"IM\/00PPS11.4","price":99.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Passive_Purple_Internal_1.png?v=1792497547"},{"product_id":"passive-purple-internal-airtight-vapour-control-paint-6-9","title":"Passive Purple Brush Home Pack 6.9kg - Airtight Paint","description":"\u003ch2\u003eWhat is Passive Purple Brush?\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePassive Purple Brush\u003c\/strong\u003e is a \u003cstrong\u003efibre-reinforced, liquid-applied airtight membrane\u003c\/strong\u003e designed for detailed airtightness work. Applied with a simple paintbrush, it creates a \u003cstrong\u003epermanent, seamless vapour-control layer\u003c\/strong\u003e that seals tricky gaps and penetrations where spraying or rolling is difficult.\u003c\/p\u003e\n\u003ch3\u003eWhere is it used?\u003c\/h3\u003e\n\u003cp\u003ePassive Purple Brush is ideal for:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eService penetrations\u003c\/strong\u003e (pipes, cables, ducts)\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eWindow and door frames\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eFloor-to-wall and wall-to-ceiling junctions\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eCracks and gaps up to 5mm\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTouch-ups after air testing\u003c\/strong\u003e or snagging\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhy use the Brush version?\u003c\/h3\u003e\n\u003cp\u003eUnlike spray-applied Passive Purple, the \u003cstrong\u003eBrush version contains fibres\u003c\/strong\u003e that span and seal larger cracks and irregularities. This makes it the go-to airtight paint for precision work, detailing, and repairs, while still delivering the same \u003cstrong\u003eairtightness performance\u003c\/strong\u003e as the Passivhaus-certified main system.\u003c\/p\u003e\n\u003ch3\u003eSurface preparation\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eEnsure surfaces are \u003cstrong\u003esolid, dust-free, and closed\u003c\/strong\u003e.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLarge gaps (\u0026gt; 5 mm):\u003c\/strong\u003e Fill with cement-based filler or foam before application.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSmall to medium gaps (2–5mm):\u003c\/strong\u003e Passive Purple Brush can be applied directly.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eApplication \u0026amp; coverage\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eApplied with a \u003cstrong\u003eflat paintbrush\u003c\/strong\u003e.\u003c\/li\u003e\n\u003cli\u003eEasy to use for small projects and detailed work.\u003c\/li\u003e\n\u003cli\u003eOnce cured, it can be \u003cstrong\u003epainted, plastered, or rendered over\u003c\/strong\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhy airtightness matters\u003c\/h3\u003e\n\u003cp\u003eAir leakage through cracks and junctions:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eReduces energy efficiency\u003c\/li\u003e\n\u003cli\u003eAllows draughts, damp, and mould\u003c\/li\u003e\n\u003cli\u003eCan compromise Passivhaus and building regulations compliance\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eBy sealing with Passive Purple Brush, you ensure every junction is airtight, securing energy performance and long-term building health.\u003c\/p\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eTested \u0026amp; Certified\u003c\/h2\u003e\n\u003cp\u003ePassive Purple Brush is covered by the same independent testing as the Passive Purple system:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFrench A+ indoor-air rating \u0026amp; Finnish M1 class\u003c\/strong\u003e - very low VOC emissions (EN 16516 \/ RTS)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePassive House Institute Class A airtight\u003c\/strong\u003e - 0.02 m³\/h·m² @ 50 Pa (EN 12114)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAir barrier material\u003c\/strong\u003e - air leakage 0.02 L\/s·m² at 75 Pa (ASTM E2178)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReaction to fire\u003c\/strong\u003e - Class A to ASTM E84 (Flame Spread 0, Smoke 35); Euroclass C-s1,d0 to EN 13501-1 (B-s1,d0 with FRED)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWatertight\u003c\/strong\u003e (EN 14891) \u0026amp; intelligent vapour control (EN ISO 12572)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStrong adhesion\u003c\/strong\u003e across substrates (EN ISO 4624) \u0026amp; \u003cstrong\u003e10\/10 mould resistance\u003c\/strong\u003e (ASTM D3273)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBBA approved\u003c\/strong\u003e; tested to ASTM E2178 and ASTM E84 (Passivhaus certification is held by Passive Purple)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eSee the full \u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Passive Purple Tested \u0026amp; Certified\"\u003etest data \u0026amp; certifications\u003c\/a\u003e, or read how Passive Purple delivers \u003ca href=\"\/en-la\/blogs\/educational\/passive-purple-cool-roof-solar-reflectance-sri-52\" title=\"Passive Purple Solar-Reflective Performance (SRI 52)\"\u003esolar-reflective performance (SRI 52)\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003e🇺🇸 \u003cstrong\u003eUS projects:\u003c\/strong\u003e tested to ASTM standards for world markets - \u003ca href=\"\/en-la\/pages\/us-specifications\" title=\"US specifications in CSI MasterFormat\"\u003edownload the US specifications (CSI MasterFormat)\u003c\/a\u003e or order through \u003ca href=\"\/en-la\/pages\/chicago\" title=\"Passive Purple Chicago — distributed and installed by WickRight\"\u003eWickRight, our Chicago distribution \u0026amp; installation partner\u003c\/a\u003e.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eHelpful guides related to this product:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/what-does-passive-purple-stick-to-adhesion-testing\" title=\"What does Passive Purple stick to?\"\u003eWhat Does Passive Purple Stick To? Adhesion Testing\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/builder-forgot-the-vapour-control-layer-how-to-fix-it\" title=\"My Builder Forgot the Vapour Control Layer? Here’s How to Fix It\"\u003eMy Builder Forgot the Vapour Control Layer? Here’s How to Fix It\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/what-is-a-vapour-control-layer-vcl-explained\" title=\"What Is a Vapour Control Layer? | VCL Explained\"\u003eWhat Is a Vapour Control Layer? | VCL Explained\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/the-airtightness-challenge-facing-modern-construction-why-blockwork-alone-is-no-longer-enough\" title=\"The Airtightness Challenge: Why Blockwork Alone Is No Longer Enough\"\u003eThe Airtightness Challenge: Why Blockwork Alone Is No Longer Enough\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/grand-designs-passivhaus-premium-uses-airtight-membrane\" title=\"Grand Designs Passivhaus Premium Uses Airtight Membrane\"\u003eGrand Designs Passivhaus Premium Uses Airtight Membrane\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eQuality assurance:\u003c\/strong\u003e \u003ca href=\"\/en-la\/pages\/qa-sign-off-downloads\"\u003eDownload the free Installation \u0026amp; QA Record sign-off sheet (IM-QA-02)\u003c\/a\u003e for this product.\u003c\/p\u003e","brand":"Intelligent Membranes","offers":[{"title":"6.9kg","offer_id":53767114850644,"sku":"IM\/00PPB6.9","price":59.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Passive_Purple_Home_Pack_1.png?v=1792498643"},{"product_id":"facade-waterproofing-membrane-5kg","title":"Passive Purple External Airtight Fire Rated Façade Waterproofing Membrane (5kg) - Purple Brush","description":"\u003cp\u003e\u003cspan data-teams=\"true\"\u003ePassive Purple External Brush, specifically designed to seal joints and gaps with precision and durability. This advanced liquid-applied weather barrier is perfect for external applications where airtightness and weather protection are critical. The brush version contains specialised fibres, allowing it to span larger gaps and joints, delivering exceptional coverage and performance in challenging areas.\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eTested \u0026amp; Certified - fire-rated, watertight \u0026amp; breathable\u003c\/h2\u003e\n\u003cp\u003eIndependently certified to both European (EN) and US (ASTM) standards:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eReaction to fire Euroclass B-s1,d0\u003c\/strong\u003e (EN 13501-1, on A1 substrates ≥653 kg\/m³) \u0026amp; \u003cstrong\u003eASTM E84 Class A\u003c\/strong\u003e (Flame Spread 0 \/ Smoke 15)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWatertight Class W1\u003c\/strong\u003e (EN 13859-2) \u0026amp; water permeability Class W3 (EN 1062-3); near-zero water absorption (EN 16302)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBreathable \/ vapour-open\u003c\/strong\u003e - Sd ≈ 0.6 m (EN ISO 12572)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrack-bridging\u003c\/strong\u003e A3 (23°C) \/ A4 (-10°C) (EN 1062-7) \u0026amp; CO₂ \/ carbonation barrier Class C1 (EN 1062-6)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUV-stable\u003c\/strong\u003e (strength increases after 500 h UV) · low-emission \u003cstrong\u003eEMICODE EC2\u003c\/strong\u003e · anti-fungus (rating 0)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eKiwa BDA Agrément\u003c\/strong\u003e (BAW-21-214-P-A-UK) · Passive House component (phB) · tested to ICC-ES AC212 criteria (water-resistive barrier)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Tested \u0026amp; Certified\"\u003eSee all test data \u0026amp; certifications →\u003c\/a\u003e · read about \u003ca href=\"\/en-la\/blogs\/educational\/passive-purple-external-fire-class-b-watertight-breathable\"\u003ePassive Purple External\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eHelpful guides related to this product:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/airtight-and-vapour-control-for-high-rise-re-cladding-installed-from-the-outside-i\" title=\"Airtight and Vapour Control for High-Rise Re-Cladding\"\u003eAirtight and Vapour Control for High-Rise Re-Cladding\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/what-is-airtightness-and-why-it-matters-for-net-zero-buildings\" title=\"What is Airtightness (and Why It Matters for Net Zero Buildings)\"\u003eWhat is Airtightness (and Why It Matters for Net Zero Buildings)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/damp-walls-two-breathable-solutions-that-actually-work\" title=\"Damp Walls? Two Breathable Solutions That Actually Work\"\u003eDamp Walls? Two Breathable Solutions That Actually Work\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eQuality assurance:\u003c\/strong\u003e \u003ca href=\"\/en-la\/pages\/qa-sign-off-downloads\"\u003eDownload the free Installation \u0026amp; QA Record sign-off sheet (IM-QA-05)\u003c\/a\u003e for this product.\u003c\/p\u003e","brand":"Intelligent Membranes","offers":[{"title":"Purple","offer_id":52682707665236,"sku":"IM\/00PPEB5","price":55.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Passive_Purple_External_Brush.png?v=1792744807"},{"product_id":"brush-applied-facade-waterproofing-membrane-5kg-bundle","title":"Passive Purple External Brush Pack","description":"\u003cspan lang=\"EN-GB\"\u003eExcelling characteristics of passive purple external: \u003c\/span\u003e\r\n\u003cul type=\"disc\"\u003e\r\n \t\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eFire Class B\u003c\/span\u003e\u003c\/li\u003e\r\n \t\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eRaintight but vapour breathable\u003c\/span\u003e\u003c\/li\u003e\r\n \t\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eAirtight\u003c\/span\u003e\u003c\/li\u003e\r\n \t\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eUV resistant\u003c\/span\u003e\u003c\/li\u003e\r\n \t\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eAnti fungus\u003c\/span\u003e\u003c\/li\u003e\r\n \t\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eSelf-cleaning \/ reduced dirt pickup caused by UV netting\u003c\/span\u003e\u003c\/li\u003e\r\n \t\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eCrack-bridging\u003c\/span\u003e\u003c\/li\u003e\r\n \t\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eCarbonatation block (for concrete); realkalising (concrete)\u003c\/span\u003e\u003c\/li\u003e\r\n \t\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eProtection against salts (for roads) (concrete structures).\u003c\/span\u003e\u003c\/li\u003e\r\n \t\u003cli\u003eCan also be used as a protective coating on concrete as anti-carbonation on concrete \/ cement coating.\u003c\/li\u003e\r\n \t\u003cli\u003e1kg will cover 1m2\u003c\/li\u003e\r\n\u003c\/ul\u003e\n\u003cdiv style=\"border-top:2px solid #b5985a;margin-top:28px;padding-top:18px;\"\u003e\n\u003ch2 style=\"color:#4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eHelpful guides related to this product:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/airtight-and-vapour-control-for-high-rise-re-cladding-installed-from-the-outside-i\" title=\"Airtight and Vapour Control for High-Rise Re-Cladding\"\u003eAirtight and Vapour Control for High-Rise Re-Cladding\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/what-is-airtightness-and-why-it-matters-for-net-zero-buildings\" title=\"What is Airtightness (and Why It Matters for Net Zero Buildings)\"\u003eWhat is Airtightness (and Why It Matters for Net Zero Buildings)\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e","brand":"Intelligent Membranes","offers":[{"title":"Default Title","offer_id":52608802062676,"sku":"IM\/00PPEBRB","price":64.98,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/passive_purple_external_brush_pack.png?v=1793205418"},{"product_id":"passive-purple-x-fire-class-b-airtight-paint-5kg","title":"Passive Purple X (5kg) Brush Applied","description":"\u003cp\u003e\u003cspan lang=\"EN-GB\"\u003eKey characteristics of Passive Purple X (shares Passive Purple External's tested performance): \u003c\/span\u003e\u003c\/p\u003e\n\u003cul type=\"disc\"\u003e\n\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eRaintight but vapour breathable\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eAirtight\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eUV resistant\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eAnti fungus\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eSelf-cleaning \/ reduced dirt pickup caused by UV netting\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eCrack-bridging\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eCarbonatation block (for concrete); realkalising (concrete)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan lang=\"EN-GB\"\u003eProtection against salts (for roads) (concrete structures).\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003eCan also be used as a protective coating on concrete as anti-carbonation on concrete \/ cement coating.\u003c\/li\u003e\n\u003cli\u003e1kg will cover 1m2\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eTested — fire-rated, watertight \u0026amp; breathable\u003c\/h2\u003e\n\u003cp\u003ePassive Purple X shares the tested performance of Passive Purple External, which has been independently tested to both European (EN) and US (ASTM) standards:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e🔥 \u003cstrong\u003eReaction to fire Euroclass B-s1,d0\u003c\/strong\u003e (EN 13501-1, on A1 substrates ≥653 kg\/m³) \u0026amp; \u003cstrong\u003eASTM E84 Class A\u003c\/strong\u003e (Flame Spread 0 \/ Smoke 15)\u003c\/li\u003e\n\u003cli\u003e💧 \u003cstrong\u003eWatertight Class W1\u003c\/strong\u003e (EN 13859-2) \u0026amp; water permeability Class W3 (EN 1062-3)\u003c\/li\u003e\n\u003cli\u003e🌬️ \u003cstrong\u003eBreathable \/ vapour-open\u003c\/strong\u003e — Sd ≈ 0.6 m (EN ISO 12572)\u003c\/li\u003e\n\u003cli\u003e🧱 \u003cstrong\u003eCrack-bridging\u003c\/strong\u003e A3 (23°C) \/ A4 (-10°C) (EN 1062-7) \u0026amp; CO₂ \/ carbonation barrier Class C1 (EN 1062-6)\u003c\/li\u003e\n\u003cli\u003e🇬🇧 \u003cstrong\u003eCertificates\u003c\/strong\u003e — Kiwa BDA Agrément (BAW-21-214-P-A-UK) and Passive House component (phB) are issued for Passive Purple External, not for Passive Purple X · Passive Purple External tested to ICC-ES AC212 criteria (water-resistive barrier)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Tested \u0026amp; Certified\"\u003eSee all test data \u0026amp; certifications →\u003c\/a\u003e · \u003ca href=\"\/en-la\/blogs\/educational\/passive-purple-external-fire-class-b-watertight-breathable\"\u003ePassive Purple External explained\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eHelpful guides related to this product:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/airtight-and-vapour-control-for-high-rise-re-cladding-installed-from-the-outside-i\" title=\"Airtight and Vapour Control for High-Rise Re-Cladding\"\u003eAirtight and Vapour Control for High-Rise Re-Cladding\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/the-airtightness-challenge-facing-modern-construction-why-blockwork-alone-is-no-longer-enough\" title=\"The Airtightness Challenge: Why Blockwork Alone Is No Longer Enough\"\u003eThe Airtightness Challenge: Why Blockwork Alone Is No Longer Enough\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/how-to-retrofit-vapour-control-without-the-mess-bba-approved-passivhaus-certified-building-control-ready\" title=\"How to Retrofit Vapour Control Without the Mess\"\u003eHow to Retrofit Vapour Control Without the Mess\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eQuality assurance:\u003c\/strong\u003e \u003ca href=\"\/en-la\/pages\/qa-sign-off-downloads\"\u003eDownload the free Installation \u0026amp; QA Record sign-off sheet (IM-QA-06)\u003c\/a\u003e for this product.\u003c\/p\u003e","brand":"Intelligent Membranes","offers":[{"title":"Purple","offer_id":52682702258516,"sku":"IM\/00PPXB5PURPLE","price":55.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Passive_Purple_External_Brush_2.png?v=1792672914"},{"product_id":"passivhaus-airtight-sealant","title":"Passivhaus Airtight Sealant - 600ml","description":"\u003cp\u003e\u003cstrong\u003ePassive Purple Sealant Tubes – Perfect for Airtight Sealing of Gaps in the Building Fabric\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePassive Purple\u003c\/strong\u003e brush in convenient sealant tubes is the ultimate solution for air-sealing gaps and cracks in the building fabric, ensuring airtightness and improved energy efficiency. This flexible, liquid-applied sealant is specifically formulated for quick and easy application, making it ideal for sealing joints, penetrations, and gaps in walls, floors, and ceilings. Designed to meet the highest airtightness standards, \u003cstrong\u003ePassive Purple\u003c\/strong\u003e helps reduce energy loss and is suitable for both new-build and retrofit projects.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eKey Features and Benefits:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eEfficient Air Sealing:\u003c\/strong\u003e Passive Purple sealant is ideal for sealing gaps and cracks in the building envelope, creating an airtight barrier that prevents air leakage and improves thermal performance. Perfect for use around windows, doors, service penetrations, and joints.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQuick and Easy Application:\u003c\/strong\u003e Sealant tubes allow Passive Purple to be applied directly into gaps and joints using a standard caulking gun, providing precise control and a smooth, seamless finish.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVersatile Use:\u003c\/strong\u003e Suitable for a wide range of substrates including timber, concrete, brick, and plasterboard.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurable and Long-Lasting:\u003c\/strong\u003e Once applied, Passive Purple forms a flexible, durable seal that accommodates building movement and environmental changes while maintaining airtightness.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEnergy Efficiency:\u003c\/strong\u003e By eliminating air leaks, Passive Purple helps reduce energy loss, lowers heating and cooling costs, and supports energy-efficient, sustainable construction.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eWhy Choose Passive Purple in Sealant Tubes?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecision Application:\u003c\/strong\u003e Sealant tubes allow targeted application, ensuring even the smallest gaps are effectively sealed.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImproved Energy Performance:\u003c\/strong\u003e Sealing gaps with Passive Purple significantly reduces air infiltration, improving comfort and overall thermal performance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePerfect for Retrofit and New Builds:\u003c\/strong\u003e Whether sealing a new building or upgrading an existing structure, Passive Purple sealant tubes offer a practical and reliable airtightness solution.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAchieve superior airtightness with \u003cstrong\u003ePassive Purple Sealant Tubes\u003c\/strong\u003e — an easy-to-use, flexible solution for sealing gaps in the building fabric. Ideal for improving energy efficiency and sealing joints in both new and retrofit projects, \u003cstrong\u003ePassive Purple\u003c\/strong\u003e delivers a durable, long-lasting airtight seal.\u003c\/p\u003e\n\u003cp\u003eEach sausage covers approximately \u003cstrong\u003e6 linear metres\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cdiv style=\"border-top:2px solid #b5985a;margin-top:28px;padding-top:18px;\"\u003e\n\u003ch2 style=\"color:#4a1a6e;\"\u003eTest data — worldwide\u003c\/h2\u003e\n\u003cp\u003ePassive Purple in sealant tubes is the same Passive Purple liquid airtight membrane formulation. Passive Purple has been independently tested to \u003cstrong\u003eboth ASTM and EN standards\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e🌿 \u003cstrong\u003eFrench A+ indoor-air rating \u0026amp; Finnish M1 class\u003c\/strong\u003e — very low VOC emissions (EN 16516 \/ RTS)\u003c\/li\u003e\n\u003cli\u003e🏠 \u003cstrong\u003ePassive House Institute Class A airtight\u003c\/strong\u003e — 0.02 m³\/h·m² @ 50 Pa (EN 12114)\u003c\/li\u003e\n\u003cli\u003e🔒 \u003cstrong\u003eAir barrier material\u003c\/strong\u003e — 0.02 L\/s·m² at 75 Pa (ASTM E2178)\u003c\/li\u003e\n\u003cli\u003e🔥 \u003cstrong\u003eReaction to fire\u003c\/strong\u003e — Class A to ASTM E84; Euroclass C-s1,d0 to EN 13501-1 (B-s1,d0 with FRED)\u003c\/li\u003e\n\u003cli\u003e💧 \u003cstrong\u003eWatertight\u003c\/strong\u003e (EN 14891) \u0026amp; intelligent vapour control, Sd ~0.8–40 m (EN ISO 12572)\u003c\/li\u003e\n\u003cli\u003e🧱 \u003cstrong\u003eStrong adhesion\u003c\/strong\u003e — steel 2.7, CLT 1.83, gypsum 1.6, brick 1.5 N\/mm² (EN ISO 4624)\u003c\/li\u003e\n\u003cli\u003e🦠 \u003cstrong\u003e10\/10 mould resistance\u003c\/strong\u003e (ASTM D3273) · 🛡️ radon \u0026amp; methane barrier · ♻️ EPD (EN 15804)\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003eCertificates\u003c\/strong\u003e — Passivhaus certification and BBA approval are held by Passive Purple, not by this sealant\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Passive Purple Tested \u0026amp; Certified\"\u003eSee all test data \u0026amp; certifications →\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top:2px solid #b5985a;margin-top:28px;padding-top:18px;\"\u003e\n\u003ch2 style=\"color:#4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eHelpful guides related to this product:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/builder-forgot-the-vapour-control-layer-how-to-fix-it\" title=\"My Builder Forgot the Vapour Control Layer? Here’s How to Fix It\"\u003eMy Builder Forgot the Vapour Control Layer? Here’s How to Fix It\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/what-is-a-vapour-control-layer-vcl-explained\" title=\"What Is a Vapour Control Layer? | VCL Explained\"\u003eWhat Is a Vapour Control Layer? | VCL Explained\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/what-is-airtightness-and-why-it-matters-for-net-zero-buildings\" title=\"What is Airtightness (and Why It Matters for Net Zero Buildings)\"\u003eWhat is Airtightness (and Why It Matters for Net Zero Buildings)\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e","brand":"Intelligent Membranes","offers":[{"title":"1","offer_id":52608802292052,"sku":"IM\/00PHSS","price":12.0,"currency_code":"GBP","in_stock":true},{"title":"12","offer_id":52608802324820,"sku":"IM\/00PHSB","price":144.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Passivhaus-Sealant_-White-and-Purple_png.webp?v=1784733153"},{"product_id":"passive-purple-retrofit-airtightness-5kg","title":"Passive Purple Retrofit - Retrofit Airtightness Brush Applied Paint (5kg)","description":"\u003ch2\u003ePassive Purple Retrofit Brush – Breathable Airtightness for Existing Buildings\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePassive Purple Retrofit Brush\u003c\/strong\u003e is a fibre-reinforced, liquid-applied airtight membrane for older and solid-wall buildings that need to breathe. Brushed on internally, it seals joints, gaps, cracks and junctions against draughts and air leakage while staying \u003cstrong\u003evapour open (Sd ≈ 0.6 m)\u003c\/strong\u003e, so moisture in the wall can still dry out.\u003c\/p\u003e\n\u003ch2\u003eWhy Do Older Buildings Need a Breathable Airtight Layer?\u003c\/h2\u003e\n\u003cp\u003eSolid brick, stone and lime-plastered walls were built to manage moisture by letting it move through the wall and dry out. Sealing them with a vapour-tight layer can trap that moisture in the fabric, leading to damp, mould and decay.\u003c\/p\u003e\n\u003cp\u003ePassive Purple Retrofit stops the air leaks that cause heat loss and draughts, but still lets water vapour pass through – so the wall keeps working the way it was designed to.\u003c\/p\u003e\n\u003ch2\u003ePassive Purple or Passive Purple Retrofit?\u003c\/h2\u003e\n\u003ctable style=\"width:100%;border-collapse:collapse;margin:16px 0;\"\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth style=\"background:#4a1a6e;color:#fff;padding:10px 12px;text-align:left;\"\u003e\u003c\/th\u003e\n\u003cth style=\"background:#4a1a6e;color:#fff;padding:10px 12px;text-align:left;\"\u003ePassive Purple\u003c\/th\u003e\n\u003cth style=\"background:#4a1a6e;color:#fff;padding:10px 12px;text-align:left;\"\u003ePassive Purple Retrofit\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:10px 12px;border-bottom:1px solid #e0d3ef;\"\u003e\u003cstrong\u003eVapour behaviour\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px;border-bottom:1px solid #e0d3ef;\"\u003eVapour control\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px;border-bottom:1px solid #e0d3ef;\"\u003eVapour open (breathable)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:10px 12px;border-bottom:1px solid #e0d3ef;\"\u003e\u003cstrong\u003eBest for\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px;border-bottom:1px solid #e0d3ef;\"\u003eNew builds and insulated build-ups – applied on the warm side of the insulation\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px;border-bottom:1px solid #e0d3ef;\"\u003eOlder, solid-wall and breathable buildings where moisture must be able to dry out\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:10px 12px;border-bottom:1px solid #e0d3ef;\"\u003e\u003cstrong\u003eAirtight\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px;border-bottom:1px solid #e0d3ef;\"\u003eYes\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px;border-bottom:1px solid #e0d3ef;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eNot sure which you need? Our \u003ca href=\"\/en-la\/pages\/condensation-risk-analysis\" title=\"Condensation Risk Analysis UK\"\u003econdensation risk analysis\u003c\/a\u003e will tell you, or see \u003ca href=\"\/en-la\/products\/passive-purple-internal-airtight-vapour-control-paint-11-4kg\" title=\"Passive Purple vapour control paint\"\u003ePassive Purple\u003c\/a\u003e for vapour control.\u003c\/p\u003e\n\u003ch2\u003eKey Benefits\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFibre-reinforced:\u003c\/strong\u003e spans larger joints and gaps for reliable detailing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAirtight \u0026amp; smoke-tight:\u003c\/strong\u003e stops draughts and uncontrolled air leakage.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBreathable:\u003c\/strong\u003e vapour open (Sd ≈ 0.6 m) so walls can keep drying out.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrack-bridging:\u003c\/strong\u003e stays sealed as older buildings move.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnti-fungus:\u003c\/strong\u003e resists mould growth on the coating.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow emission:\u003c\/strong\u003e EMICODE EC2 rated.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFire-rated:\u003c\/strong\u003e Euroclass B-s1,d0.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrush applied:\u003c\/strong\u003e no specialist equipment – ideal for smaller rooms, detailing and DIY retrofits.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWhere to Use It\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eJoints, gaps and cracks in older walls\u003c\/li\u003e\n\u003cli\u003eJunctions around windows, doors, floors and ceilings\u003c\/li\u003e\n\u003cli\u003ePipe, cable and joist penetrations\u003c\/li\u003e\n\u003cli\u003eSolid brick, stone and lime-plastered walls\u003c\/li\u003e\n\u003cli\u003eSmaller rooms and period homes\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eFor large walls and ceilings, use \u003ca href=\"\/en-la\/products\/passive-purple-retrofit-airtightness-10kg\" title=\"Passive Purple Retrofit Spray\/Roller\"\u003ePassive Purple Retrofit Spray\/Roller (10kg)\u003c\/a\u003e for faster coverage.\u003c\/p\u003e\n\u003cdiv style=\"border-top:2px solid #b5985a;margin-top:28px;padding-top:18px;\"\u003e\n\u003ch2 style=\"color:#4a1a6e;\"\u003eTested \u0026amp; Certified — fire-rated, watertight \u0026amp; breathable\u003c\/h2\u003e\n\u003cp\u003ePassive Purple Retrofit is a product of Passive Purple External. The test results and certificates below are issued for Passive Purple External, not for the Passive Purple Retrofit product name:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e🔥 \u003cstrong\u003eReaction to fire Euroclass B-s1,d0\u003c\/strong\u003e (EN 13501-1, on A1 substrates ≥653 kg\/m³) \u0026amp; \u003cstrong\u003eASTM E84 Class A\u003c\/strong\u003e (Flame Spread 0 \/ Smoke 15)\u003c\/li\u003e\n\u003cli\u003e💧 \u003cstrong\u003eWatertight Class W1\u003c\/strong\u003e (EN 13859-2) \u0026amp; water permeability Class W3 (EN 1062-3); near-zero water absorption (EN 16302)\u003c\/li\u003e\n\u003cli\u003e🌬️ \u003cstrong\u003eBreathable \/ vapour-open\u003c\/strong\u003e — Sd ≈ 0.6 m (EN ISO 12572)\u003c\/li\u003e\n\u003cli\u003e🧱 \u003cstrong\u003eCrack-bridging\u003c\/strong\u003e A3 (23°C) \/ A4 (-10°C) (EN 1062-7) \u0026amp; CO₂ \/ carbonation barrier Class C1 (EN 1062-6)\u003c\/li\u003e\n\u003cli\u003e☀️ \u003cstrong\u003eUV-stable\u003c\/strong\u003e · low-emission \u003cstrong\u003eEMICODE EC2\u003c\/strong\u003e · anti-fungus (rating 0)\u003c\/li\u003e\n\u003cli\u003e🇬🇧 \u003cstrong\u003eKiwa BDA Agrément\u003c\/strong\u003e (BAW-21-214-P-A-UK) · Passive House component (phB) · tested to ICC-ES AC212 criteria (water-resistive barrier)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Tested \u0026amp; Certified\"\u003eSee all test data \u0026amp; certifications →\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top:2px solid #b5985a;margin-top:28px;padding-top:18px;\"\u003e\n\u003ch2 style=\"color:#4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eHelpful guides related to this product:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/how-to-retrofit-vapour-control-without-the-mess-bba-approved-passivhaus-certified-building-control-ready\" title=\"How to Retrofit Vapour Control Without the Mess\"\u003eHow to Retrofit Vapour Control Without the Mess\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/damp-walls-two-breathable-solutions-that-actually-work\" title=\"Damp Walls? Two Breathable Solutions That Actually Work\"\u003eDamp Walls? Two Breathable Solutions That Actually Work\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/enerphit-explained-the-passivhaus-standard-for-old-buildings\" title=\"EnerPHit Explained – The Passivhaus Standard for Old Buildings\"\u003eEnerPHit Explained – The Passivhaus Standard for Old Buildings\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eQuality assurance:\u003c\/strong\u003e \u003ca href=\"\/en-la\/pages\/qa-sign-off-downloads\"\u003eDownload the free Installation \u0026amp; QA Record sign-off sheet (IM-QA-07)\u003c\/a\u003e for this product.\u003c\/p\u003e","brand":"Intelligent Membranes","offers":[{"title":"Purple","offer_id":52682700194132,"sku":"IM\/00RETB5PURPLE","price":55.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Passive_Purple_Retrofit_Brush_1.png?v=1792748153"},{"product_id":"passive-purple-retrofit-airtightness-10kg","title":"Passive Purple Retrofit - Retrofit Airtightness Spray\/Roller Paint (10kg)","description":"\u003ch2\u003ePassive Purple Retrofit – Breathable Airtightness for Existing Buildings\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePassive Purple Retrofit\u003c\/strong\u003e is a liquid-applied airtight membrane for older and solid-wall buildings that need to breathe. Sprayed or rolled on internally, it seals walls, ceilings and junctions against draughts and air leakage while staying \u003cstrong\u003evapour open (Sd ≈ 0.6 m)\u003c\/strong\u003e, so moisture in the wall can still dry out.\u003c\/p\u003e\n\u003ch2\u003eWhy Do Older Buildings Need a Breathable Airtight Layer?\u003c\/h2\u003e\n\u003cp\u003eSolid brick, stone and lime-plastered walls were built to manage moisture by letting it move through the wall and dry out. Sealing them with a vapour-tight layer can trap that moisture in the fabric, leading to damp, mould and decay.\u003c\/p\u003e\n\u003cp\u003ePassive Purple Retrofit stops the air leaks that cause heat loss and draughts, but still lets water vapour pass through – so the wall keeps working the way it was designed to.\u003c\/p\u003e\n\u003ch2\u003ePassive Purple or Passive Purple Retrofit?\u003c\/h2\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse; margin: 16px 0;\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth style=\"background: #4a1a6e; color: #fff; padding: 10px 12px; text-align: left;\"\u003e\u003c\/th\u003e\n\u003cth style=\"background: #4a1a6e; color: #fff; padding: 10px 12px; text-align: left;\"\u003ePassive Purple\u003c\/th\u003e\n\u003cth style=\"background: #4a1a6e; color: #fff; padding: 10px 12px; text-align: left;\"\u003ePassive Purple Retrofit\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px 12px; border-bottom: 1px solid #e0d3ef;\"\u003e\u003cstrong\u003eVapour behaviour\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 12px; border-bottom: 1px solid #e0d3ef;\"\u003eVapour control\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 12px; border-bottom: 1px solid #e0d3ef;\"\u003eVapour open (breathable)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px 12px; border-bottom: 1px solid #e0d3ef;\"\u003e\u003cstrong\u003eBest for\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 12px; border-bottom: 1px solid #e0d3ef;\"\u003eNew builds and insulated build-ups – applied on the warm side of the insulation\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 12px; border-bottom: 1px solid #e0d3ef;\"\u003eOlder, solid-wall and breathable buildings where moisture must be able to dry out\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 10px 12px; border-bottom: 1px solid #e0d3ef;\"\u003e\u003cstrong\u003eAirtight\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 12px; border-bottom: 1px solid #e0d3ef;\"\u003eYes\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 12px; border-bottom: 1px solid #e0d3ef;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eNot sure which you need? Our \u003ca href=\"\/en-la\/pages\/condensation-risk-analysis\" title=\"Condensation Risk Analysis UK\"\u003econdensation risk analysis\u003c\/a\u003e will tell you, or see \u003ca href=\"\/en-la\/products\/passive-purple-internal-airtight-vapour-control-paint-11-4kg\" title=\"Passive Purple vapour control paint\"\u003ePassive Purple\u003c\/a\u003e for vapour control.\u003c\/p\u003e\n\u003ch2\u003eKey Benefits\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAirtight \u0026amp; smoke-tight:\u003c\/strong\u003e stops draughts and uncontrolled air leakage.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBreathable:\u003c\/strong\u003e vapour open (Sd ≈ 0.6 m) so walls can keep drying out.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrack-bridging:\u003c\/strong\u003e stays sealed as older buildings move.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnti-fungus:\u003c\/strong\u003e resists mould growth on the coating.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow emission:\u003c\/strong\u003e EMICODE EC2 rated.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFire-rated:\u003c\/strong\u003e Euroclass B-s1,d0.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeamless:\u003c\/strong\u003e no tapes, laps or weak points – seals around pipes, cables and joists.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpray or roller:\u003c\/strong\u003e fast, even coverage on large walls and ceilings.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWhere to Use It\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eSolid brick and stone walls\u003c\/li\u003e\n\u003cli\u003eLime-plastered walls\u003c\/li\u003e\n\u003cli\u003ePeriod and traditional homes\u003c\/li\u003e\n\u003cli\u003eCeilings, junctions and service penetrations\u003c\/li\u003e\n\u003cli\u003eTimber-frame and mixed-construction retrofits\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eFor joints, gaps and detailing, use \u003ca href=\"\/en-la\/products\/passive-purple-retrofit-airtightness-5kg\" title=\"Passive Purple Retrofit Brush\"\u003ePassive Purple Retrofit Brush\u003c\/a\u003e, a fibre-reinforced brush grade.\u003c\/p\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eTested \u0026amp; Certified - fire-rated, watertight \u0026amp; breathable\u003c\/h2\u003e\n\u003cp\u003ePassive Purple Retrofit is a product of Passive Purple External. The test results and certificates below are issued for Passive Purple External, not for the Passive Purple Retrofit product name:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eReaction to fire Euroclass B-s1,d0\u003c\/strong\u003e (EN 13501-1, on A1 substrates ≥653 kg\/m³) \u0026amp; \u003cstrong\u003eASTM E84 Class A\u003c\/strong\u003e (Flame Spread 0 \/ Smoke 15)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWatertight Class W1\u003c\/strong\u003e (EN 13859-2) \u0026amp; water permeability Class W3 (EN 1062-3); near-zero water absorption (EN 16302)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBreathable \/ vapour-open\u003c\/strong\u003e — Sd ≈ 0.6 m (EN ISO 12572)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrack-bridging\u003c\/strong\u003e A3 (23°C) \/ A4 (-10°C) (EN 1062-7) \u0026amp; CO₂ \/ carbonation barrier Class C1 (EN 1062-6)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUV-stable\u003c\/strong\u003e · low-emission \u003cstrong\u003eEMICODE EC2\u003c\/strong\u003e · anti-fungus (rating 0)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eKiwa BDA Agrément\u003c\/strong\u003e (BAW-21-214-P-A-UK) · Passive House component (phB) · tested to ICC-ES AC212 criteria (water-resistive barrier)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Tested \u0026amp; Certified\"\u003eSee all test data \u0026amp; certifications →\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eHelpful guides related to this product:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/how-to-retrofit-vapour-control-without-the-mess-bba-approved-passivhaus-certified-building-control-ready\" title=\"How to Retrofit Vapour Control Without the Mess\"\u003eHow to Retrofit Vapour Control Without the Mess\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/damp-walls-two-breathable-solutions-that-actually-work\" title=\"Damp Walls? Two Breathable Solutions That Actually Work\"\u003eDamp Walls? Two Breathable Solutions That Actually Work\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/enerphit-explained-the-passivhaus-standard-for-old-buildings\" title=\"EnerPHit Explained – The Passivhaus Standard for Old Buildings\"\u003eEnerPHit Explained – The Passivhaus Standard for Old Buildings\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eQuality assurance:\u003c\/strong\u003e \u003ca href=\"\/en-la\/pages\/qa-sign-off-downloads\"\u003eDownload the free Installation \u0026amp; QA Record sign-off sheet (IM-QA-07)\u003c\/a\u003e for this product.\u003c\/p\u003e","brand":"Intelligent Membranes","offers":[{"title":"Purple","offer_id":52682698490196,"sku":"IM\/00RETS10PURPLE","price":119.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Passive_Purple_Retrofit_1.png?v=1792748141"},{"product_id":"passive-purple-x-10kg-white-spray-roller","title":"Passive Purple X (10kg) - Spray\/Roller","description":"\u003ch2\u003eWhat is Passive Purple X and How Does it Work?\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePassive Purple X\u003c\/strong\u003e is a \u003cstrong\u003efire-rated, airtight, watertight and breathable liquid membrane\u003c\/strong\u003e for new-build projects. It is \u003cstrong\u003espray or roller-applied\u003c\/strong\u003e to form one seamless coating, replacing the separate layers and laps of a traditional membrane.\u003c\/p\u003e\n\u003cp\u003eApplied \u003cstrong\u003einternally or externally\u003c\/strong\u003e, it stops air and rain getting through while allowing water vapour to escape, so the building fabric can dry out. It's available in \u003cstrong\u003ewhite, cream, black or purple\u003c\/strong\u003e and shares the tested performance of \u003ca href=\"\/en-la\/products\/passive-purple-external-airtight-fire-rated-facade-waterproofing-membrane-10kg-cream-spray-roller\" title=\"Passive Purple External\"\u003ePassive Purple External\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eWhy Breathable Airtight Paint?\u003c\/h2\u003e\n\u003cp\u003eTrapped moisture can damage the building fabric, so a wall needs to keep out air and rain while still being able to dry. Using separate products for fire, water, air and vapour also creates more interfaces where a detail can fail.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePassive Purple X brings those functions together in one continuous layer.\u003c\/strong\u003e With a vapour resistance of \u003cstrong\u003eSd ≈ 0.6 m\u003c\/strong\u003e, it lets moisture escape while the coating sheds rain.\u003c\/p\u003e\n\u003cp\u003eIt isn't a vapour control layer. Where your design needs one, use \u003ca href=\"\/en-la\/products\/passive-purple-internal-airtight-vapour-control-paint-11-4kg\" title=\"Passive Purple\"\u003ePassive Purple\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eSpray \/ Roller or Brush Application\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpray application:\u003c\/strong\u003e Using an airless machine, one installer can cover up to \u003cstrong\u003e300 m² per day\u003c\/strong\u003e.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRoller application:\u003c\/strong\u003e Ideal if you don't have a spray machine to hand.\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-la\/products\/passive-purple-x-fire-class-b-airtight-paint-5kg\" title=\"Passive Purple X Brush\"\u003e\u003cstrong\u003eBrush application (Passive Purple X Brush):\u003c\/strong\u003e\u003c\/a\u003e A 5kg brush-applied version.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSuitability of Passive Purple X\u003c\/h2\u003e\n\u003cp\u003ePassive Purple X is designed primarily for \u003cstrong\u003enew builds\u003c\/strong\u003e, for internal and external use, and can be applied to:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eConcrete, brick and blockwork\u003c\/li\u003e\n\u003cli\u003eOSB and engineered timber panels\u003c\/li\u003e\n\u003cli\u003eFibre cement boards and plasterboard\u003c\/li\u003e\n\u003cli\u003eInsulation panels\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eWorking on an existing building?\u003c\/strong\u003e Take a look at \u003ca href=\"\/en-la\/products\/passive-purple-retrofit-airtightness-10kg\" title=\"Passive Purple Retrofit\"\u003ePassive Purple Retrofit\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFire rating:\u003c\/strong\u003e The Euroclass B-s1,d0 classification applies on A1 substrates with a density of at least 653 kg\/m³. The designer and building control body should confirm suitability against the building's fire strategy.\u003c\/p\u003e\n\u003ch2\u003eThe Benefits of Passive Purple X\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e✅ \u003cstrong\u003eFire rated:\u003c\/strong\u003e Euroclass B-s1,d0 on qualifying substrates and ASTM E84 Class A\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003eAirtight and smoke-tight:\u003c\/strong\u003e One continuous, seamless layer\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003eWatertight but breathable:\u003c\/strong\u003e Keeps rain out and lets vapour escape\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003eCrack-bridging:\u003c\/strong\u003e Tested at 23°C and -10°C\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003eUV-stable:\u003c\/strong\u003e Tensile strength increases after 500 hours of UV exposure\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003eProtects concrete:\u003c\/strong\u003e Class C1 CO₂ and carbonation barrier\u003c\/li\u003e\n\u003cli\u003e✅ \u003cstrong\u003eWater-based and low emission:\u003c\/strong\u003e EMICODE EC2 rated\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eAirtightness and Breathability, Explained\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat is airtightness?\u003c\/strong\u003e Controlling unintended air leakage through the building fabric.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat does breathable mean?\u003c\/strong\u003e Water vapour can pass through the membrane, while liquid water and air can't.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat are the airtightness standards?\u003c\/strong\u003e New homes in England must achieve 8 m³\/(h·m²) at 50 Pa or better, while Passivhaus requires ≤0.6 ACH.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhy does it matter?\u003c\/strong\u003e Good airtightness reduces energy loss and improves comfort, while breathability allows the building fabric to dry.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003ePassive Purple X and Passivhaus\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat is Passivhaus?\u003c\/strong\u003e A building standard focused on extreme energy efficiency and occupant comfort.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat are the five principles?\u003c\/strong\u003e Airtightness, insulation, high-performance glazing, thermal bridge-free design, and ventilation with heat recovery.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWhat is the certification?\u003c\/strong\u003e Passive Purple X does not hold its own certificates. The Passive House Institute component certificate (\u003cstrong\u003eClass phB\u003c\/strong\u003e) and Kiwa BDA Agrément are issued for Passive Purple External.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003ePreparation \u0026amp; Application\u003c\/h2\u003e\n\u003cp\u003eGreat airtightness starts with the right prep:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eRemove salt efflorescence, dust, loose material and standing water. Damp surfaces are fine.\u003c\/li\u003e\n\u003cli\u003eMake sure the surface is closed, filling holes and joints with a fast-setting cement-based product or polyurethane foam.\u003c\/li\u003e\n\u003cli\u003eDon't add water or solvents.\u003c\/li\u003e\n\u003cli\u003eDon't apply below 5°C (air and substrate temperature), in full sunlight or during rain.\u003c\/li\u003e\n\u003cli\u003eApply two coats, letting the first dry before applying the second.\u003c\/li\u003e\n\u003cli\u003eClean tools with water after use.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eHow Much Will You Need?\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eSubstrate\u003c\/th\u003e\n\u003cth\u003eApprox. coverage\u003c\/th\u003e\n\u003cth\u003ePer 10kg tub\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eOSB and plasterboard\u003c\/td\u003e\n\u003ctd\u003e0.8–1.0 kg\/m²\u003c\/td\u003e\n\u003ctd\u003e10–12 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlockwork and brickwork\u003c\/td\u003e\n\u003ctd\u003e1.0–1.2 kg\/m²\u003c\/td\u003e\n\u003ctd\u003e8–10 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eCoverage varies with substrate type, porosity and surface condition. Use a wet film gauge to check thickness during application.\u003c\/p\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eTested\u003c\/h2\u003e\n\u003cp\u003ePassive Purple X shares the tested performance of Passive Purple External, which has been independently tested to European (EN) and US (ASTM) standards:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eReaction to fire:\u003c\/strong\u003e Euroclass B-s1,d0 (EN 13501-1, on A1 substrates ≥653 kg\/m³) and ASTM E84 Class A (Flame Spread 0, Smoke 15)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWatertight:\u003c\/strong\u003e Class W1 (EN 13859-2), water permeability Class W3 (EN 1062-3) and near-zero water absorption (EN 16302)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBreathable:\u003c\/strong\u003e Sd ≈ 0.6 m (EN ISO 12572)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrack-bridging:\u003c\/strong\u003e A3 at 23°C and A4 at -10°C (EN 1062-7)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCarbonation barrier:\u003c\/strong\u003e CO₂ Class C1 (EN 1062-6)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdhesion:\u003c\/strong\u003e Up to 1.23 N\/mm² on CLT (EN ISO 4624)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow emission:\u003c\/strong\u003e EMICODE EC2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnti-fungus:\u003c\/strong\u003e Rating 0\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUS water-resistive barrier:\u003c\/strong\u003e Passive Purple External tested to ICC-ES AC212 criteria\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCertificates:\u003c\/strong\u003e Kiwa BDA Agrément (BAW-21-214-P-A-UK) and Passive House component (Class phB) are issued for Passive Purple External, not for Passive Purple X\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Tested \u0026amp; Certified\"\u003eSee all test data \u0026amp; certifications →\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/passive-purple-external-fire-class-b-watertight-breathable\" title=\"Passive Purple External: Fire Class B, Watertight and Breathable\"\u003ePassive Purple External: Fire Class B, Watertight and Breathable\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/airtight-and-vapour-control-for-high-rise-re-cladding-installed-from-the-outside-i\" title=\"Airtight and Vapour Control for High-Rise Re-Cladding\"\u003eAirtight and Vapour Control for High-Rise Re-Cladding\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/the-airtightness-challenge-facing-modern-construction-why-blockwork-alone-is-no-longer-enough\" title=\"The Airtightness Challenge: Why Blockwork Alone Is No Longer Enough\"\u003eThe Airtightness Challenge: Why Blockwork Alone Is No Longer Enough\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eQuality assurance:\u003c\/strong\u003e \u003ca href=\"\/en-la\/pages\/qa-sign-off-downloads\"\u003eDownload the free Installation \u0026amp; QA Record sign-off sheet (IM-QA-06)\u003c\/a\u003e for this product.\u003c\/p\u003e\n\u003ch2\u003eConnect the Membrane at Windows and Junctions\u003c\/h2\u003e\n\u003cp\u003ePlan the adjoining tape detail as well as the coated area. Our \u003ca href=\"\/en-la\/blogs\/educational\/airtightness-tape-guide\"\u003eairtightness tape guide\u003c\/a\u003e covers width and substrate selection, while \u003ca href=\"\/en-la\/blogs\/educational\/airtightness-tape-vs-liquid-airtight-membrane\"\u003etape versus liquid membrane\u003c\/a\u003e explains compatible interfaces, preparation and inspection. Use the specified coating-to-tape detail and check continuity before covering.\u003c\/p\u003e","brand":"Intelligent Membranes","offers":[{"title":"White","offer_id":52683125358932,"sku":"IM\/00PPXS10WHITE","price":119.99,"currency_code":"GBP","in_stock":true},{"title":"Cream","offer_id":52683125260628,"sku":"IM\/00PPXS10CREAM","price":119.99,"currency_code":"GBP","in_stock":true},{"title":"Black","offer_id":52683125293396,"sku":"IM\/00PPXS10BLACK","price":119.99,"currency_code":"GBP","in_stock":true},{"title":"Purple","offer_id":52683125326164,"sku":"IM\/00PPXS10PURPLE","price":119.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Passive_Purple_X_3.png?v=1792672329"},{"product_id":"passive-purple-external-airtight-fire-rated-facade-waterproofing-membrane-10kg-cream-spray-roller","title":"Passive Purple External Airtight Fire Rated Façade Waterproofing Membrane (10kg) - Spray \/ Roller","description":"\u003ch3\u003eKey Characteristics of Passive Purple External\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003ePassive Purple External\u003c\/strong\u003e is a \u003cstrong\u003eFire Class B (Euroclass B-s1,d0) liquid-applied airtight paint\u003c\/strong\u003e for both \u003cstrong\u003einternal and external applications\u003c\/strong\u003e. It combines airtightness, weather protection, and intelligent moisture management in a single certified solution.\u003c\/p\u003e\n\u003ch4\u003eKey Benefits \u0026amp; Features\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFire Class B\u003c\/strong\u003e – exceptional fire resistance, setting it apart from standard membranes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRaintight \u0026amp; Vapour Breathable\u003c\/strong\u003e – keeps water out while allowing moisture to escape, ensuring a healthy building fabric.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAirtight \u0026amp; Smoke-Tight\u003c\/strong\u003e – delivers a complete barrier to uncontrolled air leakage and smoke movement.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUV Resistant \u0026amp; Self-Cleaning\u003c\/strong\u003e – long-term durability with reduced dirt pickup and surface staining.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnti-Fungus Protection\u003c\/strong\u003e – prevents mould growth and safeguards indoor air quality.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrack-Bridging\u003c\/strong\u003e – maintains airtightness even where movement or minor cracks occur.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConcrete Protection\u003c\/strong\u003e – blocks carbonation, provides realkalisation, and shields against salts from roads and de-icing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDual Purpose\u003c\/strong\u003e – suitable for \u003cstrong\u003einternal and external\u003c\/strong\u003e applications across retrofit and new-build projects.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIntelligent Moisture Management\u003c\/strong\u003e – allows the substrate to breathe, balancing vapour openness with airtight performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eWith \u003cstrong\u003ePassive Purple External\u003c\/strong\u003e, you get \u003cstrong\u003eairtightness, weather resistance, and long-term structural protection\u003c\/strong\u003e in one advanced, certified liquid membrane, ideal for timber frame, retrofit, and high-performance construction projects.\u003c\/p\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eTested \u0026amp; Certified - fire-rated, watertight \u0026amp; breathable\u003c\/h2\u003e\n\u003cp\u003eIndependently certified to both European (EN) and US (ASTM) standards:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eReaction to fire Euroclass B-s1,d0\u003c\/strong\u003e (EN 13501-1, on A1 substrates ≥653 kg\/m³) \u0026amp; \u003cstrong\u003eASTM E84 Class A\u003c\/strong\u003e (Flame Spread 0 \/ Smoke 15)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWatertight Class W1\u003c\/strong\u003e (EN 13859-2) \u0026amp; water permeability Class W3 (EN 1062-3); near-zero water absorption (EN 16302)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBreathable \/ vapour-open\u003c\/strong\u003e - Sd ≈ 0.6 m (EN ISO 12572), so the wall dries outward\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrack-bridging\u003c\/strong\u003e A3 (23°C) \/ A4 (-10°C) (EN 1062-7) \u0026amp; CO₂ \/ carbonation barrier Class C1 (EN 1062-6)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUV-stable\u003c\/strong\u003e (strength increases after 500 h UV) · low-emission \u003cstrong\u003eEMICODE EC2\u003c\/strong\u003e · anti-fungus (rating 0)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eKiwa BDA Agrément\u003c\/strong\u003e (BAW-21-214-P-A-UK) · Passive House component (phB) · tested to ICC-ES AC212 criteria (water-resistive barrier)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/en-la\/pages\/passive-purple-tested-certified\" title=\"Tested \u0026amp; Certified\"\u003eSee all test data \u0026amp; certifications →\u003c\/a\u003e · Read about \u003ca href=\"\/en-la\/blogs\/educational\/passive-purple-external-fire-class-b-watertight-breathable\"\u003ePassive Purple External\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003e🌎 Tested for World Markets - ASTM (US) \u0026amp; EN (Europe)\u003c\/h2\u003e\n\u003cp\u003ePassive Purple External is fire-rated to \u003cstrong\u003eASTM E84 Class A (US)\u003c\/strong\u003e and \u003cstrong\u003eEN fire Class B (Europe)\u003c\/strong\u003e - tested to US ASTM standards alongside its European certifications so that the same fire-rated façade membrane can be specified on both sides of the Atlantic.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eUS architects \u0026amp; specifiers: \u003ca href=\"\/en-la\/pages\/us-specifications\" title=\"US specifications in CSI MasterFormat\"\u003edownload the US specifications (CSI MasterFormat)\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003eUS supply \u0026amp; install: \u003ca href=\"\/en-la\/pages\/chicago\" title=\"Passive Purple Chicago — distributed and installed by WickRight\"\u003eWickRight, our Chicago distribution \u0026amp; installation partner\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003eFire-rated range: \u003ca href=\"\/en-la\/collections\/fire-protection\" title=\"Fire protection collection\"\u003eshop the full fire protection collection\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"border-top: 2px solid #b5985a; margin-top: 28px; padding-top: 18px;\"\u003e\n\u003ch2 style=\"color: #4a1a6e;\"\u003eRelated Guides\u003c\/h2\u003e\n\u003cp\u003eHelpful guides related to this product:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/airtight-and-vapour-control-for-high-rise-re-cladding-installed-from-the-outside-i\" title=\"Airtight and Vapour Control for High-Rise Re-Cladding\"\u003eAirtight and Vapour Control for High-Rise Re-Cladding\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/educational\/what-is-airtightness-and-why-it-matters-for-net-zero-buildings\" title=\"What is Airtightness (and Why It Matters for Net Zero Buildings)\"\u003eWhat is Airtightness (and Why It Matters for Net Zero Buildings)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-la\/blogs\/news\/damp-walls-two-breathable-solutions-that-actually-work\" title=\"Damp Walls? Two Breathable Solutions That Actually Work\"\u003eDamp Walls? Two Breathable Solutions That Actually Work\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eQuality assurance:\u003c\/strong\u003e \u003ca href=\"\/en-la\/pages\/qa-sign-off-downloads\"\u003eDownload the free Installation \u0026amp; QA Record sign-off sheet (IM-QA-05)\u003c\/a\u003e for this product.\u003c\/p\u003e","brand":"Intelligent Membranes","offers":[{"title":"Purple","offer_id":52683132174676,"sku":"IM\/00PPE10PURPLE","price":119.99,"currency_code":"GBP","in_stock":true},{"title":"Black","offer_id":52683132141908,"sku":"IM\/00PPE10BLACK","price":119.99,"currency_code":"GBP","in_stock":true},{"title":"Cream","offer_id":52683132207444,"sku":"IM\/00PPE10CREAM","price":119.99,"currency_code":"GBP","in_stock":true},{"title":"White","offer_id":52683132240212,"sku":"IM\/00PPE10WHITE","price":119.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Passive_Purple_External_df111b0c-cf87-4d71-b782-77c1ea4093dd.png?v=1792499042"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/collections\/Airtight-White.png?v=1793269444","url":"https:\/\/intelligentmembranes.com\/en-la\/collections\/vcl-membrane-vapour-control-layer.oembed","provider":"Intelligent Membranes","version":"1.0","type":"link"}