{"title":"Passive Purple Editions","description":"\u003cp\u003ePassive Purple, whichever way you like it. This collection lines up the core editions of our airtight vapour control paint: original \u003ca href=\"\/en-la\/products\/passive-purple-internal-airtight-vapour-control-paint-11-4kg\"\u003ePassive Purple\u003c\/a\u003e in spray\/roller and brush grades, \u003ca href=\"\/en-la\/products\/airtight-white-membrane-paint\"\u003eAirtight White\u003c\/a\u003e for the same performance with a brighter finish, and the brush packs that bundle everything a smaller job needs. All editions are Passivhaus certified, BBA approved and tested to both ASTM and EN standards — pick the colour and application method, the airtightness comes as standard.\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-5kg-brush-bundle","title":"Airtight White Brush Pack","description":"\u003cstrong\u003eProduct Collection: \u003c\/strong\u003ePassive Purple Edition\r\n\u003cstrong\u003eApplied By:\u003c\/strong\u003e Brush\r\n\u003cstrong\u003eColour:\u003c\/strong\u003e White\r\n\u003cstrong\u003eSize:\u003c\/strong\u003e 6.9kg\r\n\r\nPassive Purple Edition - Airtight White brush – High technology, fibre reinforced polymer emulsion applied with a paintbrush. Dries to form a permanent vapour control membrane.\r\n\r\n\u003cstrong\u003eBrush Applied.\u003c\/strong\u003e\r\n\r\n\u003cstrong\u003eKey Points:\u003c\/strong\u003e\r\n\u003cul\u003e\r\n \t\u003cli\u003eM1 class, VOC free (volatile organic compound)\u003c\/li\u003e\r\n \t\u003cli\u003eRadon barrier\u003c\/li\u003e\r\n \t\u003cli\u003eFire class C\u003c\/li\u003e\r\n \t\u003cli\u003eUp to 300m2 a day per operative\u003c\/li\u003e\r\n \t\u003cli\u003eAdheres to any substrate\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\/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","brand":"Intelligent Membranes","offers":[{"title":"Default Title","offer_id":52608800162132,"sku":"IM\/00ATWBRB","price":64.98,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/airtight_white_brush_pack.png?v=1793205611"},{"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":"internal-airtight-vapour-control-paint-6-9kg-brush-home-pack-bundle","title":"Passive Purple Brush Pack","description":"\u003ch2\u003eWhat is Passive Purple?\u003c\/h2\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n    Passive Purple liquid airtight vapour control membrane is an airtight coating applied using an airless spray device on all areas of the external envelope (warm side of the insulation) of a building. This includes difficult connection areas such as floors, walls, roofs, and joists.\n  \u003c\/li\u003e\n\n  \u003cli\u003e\n    When Passive Purple is used on the warm side of the insulation, it can be applied to either face of the external envelope.\n  \u003c\/li\u003e\n\n  \u003cli\u003e\n    Before application, ensure the surface is solid, dust-free, and closed.\n  \u003c\/li\u003e\n\n  \u003cli\u003e\n    A closed surface means all holes and joints must be sealed beforehand:\n    \u003cul\u003e\n      \u003cli\u003e\n        \u003cstrong\u003eLarge holes and joints (\u0026gt;5mm):\u003c\/strong\u003e seal using fast-setting cement-based products or polyurethane foam.\n      \u003c\/li\u003e\n      \u003cli\u003e\n        \u003cstrong\u003eSmall holes and joints (2–5mm):\u003c\/strong\u003e seal directly using Passive Purple Liquid Brush, the thicker brush-applied version.\n      \u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/li\u003e\n\n  \u003cli\u003e\n    After preparation, Passive Purple can be spray-applied with an airless machine, allowing a single operator to apply up to \u003cstrong\u003e300m² per day\u003c\/strong\u003e.\n  \u003c\/li\u003e\n\n  \u003cli\u003e\n    For smaller projects, such as private houses, Passive Purple Brush can be applied using a flat paintbrush.\n  \u003c\/li\u003e\n\n  \u003cli\u003e\n    Wall-to-ceiling connections must also be made airtight, especially where different construction materials meet, such as brick to concrete or steel to concrete.\n  \u003c\/li\u003e\n\n  \u003cli\u003e\n    Different construction materials respond differently to changes in humidity and temperature, which can cause small cracks in finishes. These cracks may lead to air leakage, reduced energy performance, and an increased risk of damp and mould.\n  \u003c\/li\u003e\n\n  \u003cli\u003e\n    Both airtight paints can be used for wall-to-ceiling connections: Passive Purple spray-applied and Passive Purple Brush.\n  \u003c\/li\u003e\n\n  \u003cli\u003e\n    Get in touch with our team at \n    \u003ca href=\"mailto:info@intelligentmembranes.com\"\u003einfo@intelligentmembranes.com\u003c\/a\u003e \n    to learn more about Passive Purple and airtightness solutions.\n  \u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\n  \u003cstrong\u003eNote:\u003c\/strong\u003e If you do not have an airless sprayer but still wish to install Passive Purple yourself, a roller-applied version is also available. While application may take a little longer, it delivers the same reliable airtight performance.\n\u003c\/p\u003e\n\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\/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","brand":"Intelligent Membranes","offers":[{"title":"Default Title","offer_id":52608801505620,"sku":"IM\/00PPBRB","price":64.98,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/passive_purple_brush_pack.png?v=1793205462"}],"url":"https:\/\/intelligentmembranes.com\/en-la\/collections\/passive-purple-editions.oembed","provider":"Intelligent Membranes","version":"1.0","type":"link"}