Protective coating THE BIG BOY BUNDLE

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Overview
Passive Purple is a water‑based, VOC‑free liquid airtight vapour control membrane designed for building envelope applications. Applied on the warm side of the insulation, it creates a continuous airtight coating that can also function as a vapour control layer and radon barrier. Certified by BBA and as a Passivhaus component.

What is and how to use Passive Purple?

• Passive Purple is applied with an airless spray device to the warm side of the external envelope (floors, walls, roofs, joists) including difficult junctions.
• When applied on the warm side of insulation it forms a vapour control layer; it can be applied to either face of the external envelope where required.
• Surface preparation: substrate must be solid, dust‑free and closed before application; all holes and joints must be sealed.
• Large holes and joints (>5 mm): seal with fast‑setting cement‑based products or polyurethane foam.
• Small holes and joints (2–5 mm): seal using Passive Purple Liquid Brush (brush‑applied, thicker version).
• Airless spray application enables high productivity: a single installer can apply up to 300 m² per day. Brush and roller versions are available for small projects or where no airless sprayer is used.
• Ensure airtight continuity at wall‑to‑ceiling connections and interfaces between different materials to prevent air leakage, energy loss and moisture risks.

Uses and Compatible Substrates

• Concrete
• Brick
• Wood
• Floor/wall connections
• Ceiling connections
• Vertical and horizontal joints

Related guides

• What Is a Vapour Control Layer? | VCL Explained
• My Builder Forgot the Vapour Control Layer? Here’s How to Fix It
• What is Airtightness (and Why It Matters for Net Zero Buildings)

Application productivity & options

• Airless spray: up to 300 m² per installer per day (reduces labour time and construction programme).
• Brush‑applied: Passive Purple Brush for detailed sealing and small projects.
• Roller version: available for installers without airless equipment (longer application time).

Certificates & Performance Highlights

• BBA certified liquid airtight vapour control layer.
• Passivhaus certified component (measured capability 0.03 ACH; supports meeting ≤0.6 ACH).
• Acts as a radon barrier.
• M1 class, VOC‑free, water‑based product.
• Fire classification: Class C.

Technical specifications

• Product family: Passive Purple (liquid‑applied airtight vapour control membrane)
• Presentation / bundle name: The BIG BOY Bundle
• Application methods: airless spray (high productivity), brush (Passive Purple Brush), roller available
• Typical productivity: up to 300 m² per installer per day (spray)
• Substrate compatibility: concrete, brick, wood, floor/wall and ceiling connections, vertical and horizontal joints
• Surface preparation: solid, dust‑free, closed surfaces; seal >5 mm with cement or PU foam; seal 2–5 mm with brush product
• VOC / Emissions: M1 class, VOC‑free (water‑based)
• Fire classification: Class C
• Passivhaus performance: certified component; measured 0.03 ACH capability
• Additional certifications: BBA; listed in material databases (e.g. WUFI properties)