Preparation paint PASSIVE PURPLE BRUSH PACK

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What is Passive Purple?

• Passive Purple liquid airtight vapour control membrane is an airtight coating applied on the warm side of the insulation of a building (external envelope). It is used on floors, walls, roofs and joists including difficult connection areas.
• When used on the warm side of the insulation, Passive Purple can be applied to either face of the external envelope.
• Before application, ensure the surface is solid, dust-free and closed (all holes and joints sealed beforehand).
• Surface preparation guidance for holes and joints:
  • Large holes and joints (>5mm): seal using fast-setting cement-based products or polyurethane foam.
  • Small holes and joints (2–5mm): seal directly using Passive Purple Liquid Brush (the thicker brush-applied version).
• After preparation, Passive Purple can be spray-applied with an airless machine; a single operator can apply up to 300m² per day with an airless sprayer.
• For smaller projects, such as private houses, Passive Purple Brush can be applied using a flat paintbrush (brush-applied).
• Wall-to-ceiling connections must be made airtight, especially where different construction materials meet (brick to concrete, steel to concrete).
• Different construction materials respond differently to humidity and temperature changes and can develop small cracks in finishes; these cracks may lead to air leakage, reduced energy performance and an increased risk of damp and mould. Both Passive Purple spray-applied and Passive Purple Brush can be used for wall-to-ceiling connections.

Note:
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.

Related Guides

• My Builder Forgot the Vapour Control Layer? Here’s How to Fix It
• What Is a Vapour Control Layer? | VCL Explained
• How to Retrofit Vapour Control Without the Mess

Why Choose Passive Purple?

• BBA Certified & Passivhaus Certified: Passive Purple is a fully BBA certified Liquid Airtight Vapour Control Layer and a certified Passivhaus component.
• Radon Barrier: Passive Purple offers radon barrier protection to prevent radon gas ingress.
• High Productivity: A single installer can apply up to 300m² per day using an airless spray device, reducing labour costs.
• M1 Class, VOC Free: Water-based, VOC-free product (M1 class).
• Fire Class C: Rated Fire Class C (higher resistance compared with paper membranes rated E).
• Excellent Airtightness: Passivhaus certified score of 0.03 ach (well below the 0.6 ach target).

Passive Purple Uses

• Airtight flexible coating with excellent adhesion to a range of substrates including: concrete, brick and wood.
• Ideal for floor/wall connections, ceiling connections, vertical and horizontal joints.
• Also used as radon barrier protection.

Technical data

• Product collection: Passive Purple
• Applied by: Brush (this pack) — also spray or roller depending on product variant.
• Colour: Purple
• Key points:
  • Vapour control layer
  • Passivhaus certified
  • Airtight, easy-to-use brush-applied paint
  • Suitable for retrofit and new builds
  • Smoke tight
  • ICC tested and certified
  • BBA approved and certified
  • Coverage guideline: 1 kg will cover approximately 1 m² (coverage varies with application thickness and substrate)
• Brand: Intelligent Membranes
• Product name / commercial designation: Passive Purple Brush Pack
• Application methods: Brush (this pack), spray (airless) and roller (roller variant available)
• Typical coverage: ~1 kg per 1 m²; up to 300 m² per day with airless spray (single operator)
• Function: Airtight vapour control membrane / vapour control layer and radon barrier
• Certifications & standards: BBA approved, Passivhaus certified, ICC tested, M1 class (VOC free)
• Fire rating: Fire Class C
• Performance: Passivhaus certified airtightness (example score 0.03 ach referenced)
• Suitable substrates: Concrete, brick, wood, and for sealing floor/wall and ceiling connections and joints