{"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 fiber-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 drafts and air leakage while staying \u003cstrong\u003evapor 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 vapor-tight layer can trap that moisture in the fabric, leading to damp, mold and decay.\u003c\/p\u003e\n\u003cp\u003ePassive Purple Retrofit stops the air leaks that cause heat loss and drafts, but still lets water vapor 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\u003eVapor behavior\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px;border-bottom:1px solid #e0d3ef;\"\u003eVapor control\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px;border-bottom:1px solid #e0d3ef;\"\u003eVapor 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-us\/pages\/condensation-risk-analysis\" title=\"Condensation Risk Analysis UK\"\u003econdensation risk analysis\u003c\/a\u003e will tell you, or see \u003ca href=\"\/en-us\/products\/passive-purple-internal-airtight-vapour-control-paint-11-4kg\" title=\"Passive Purple vapor control paint\"\u003ePassive Purple\u003c\/a\u003e for vapor control.\u003c\/p\u003e\n\u003ch2\u003eKey Benefits\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFiber-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 drafts and uncontrolled air leakage.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBreathable:\u003c\/strong\u003e vapor 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 mold 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-us\/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, and all certification is that of Passive Purple External:\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 \/ vapor-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) · US ICC-ES AC212 water-resistive barrier\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/en-us\/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-us\/blogs\/news\/how-to-retrofit-vapour-control-without-the-mess-bba-approved-passivhaus-certified-building-control-ready\" title=\"How to Retrofit Vapor Control Without the Mess\"\u003eHow to Retrofit Vapor Control Without the Mess\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/en-us\/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-us\/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-us\/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":154.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/2104\/7636\/files\/Passive_Purple_Retrofit_Brush_1.png?v=1792748153","url":"https:\/\/intelligentmembranes.com\/en-us\/products\/passive-purple-retrofit-airtightness-5kg","provider":"Intelligent Membranes","version":"1.0","type":"link"}