The BIG BOY Bundle
The BIG BOY Bundle
What is and how to use Passive Purple?
- Passive Purple Intelligent liquid airtight vapour control membrane is an airtight coating applied using an airless spray device to 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.
- When Passive Purple Intelligent Membrane is used on the warm side of the insulation, it can be applied to either face of the external envelope to create a vapour control layer.
- To install Passive Purple Intelligent Membrane, ensure the surface is solid, dust-free, and closed before starting the application.
- A closed surface means all holes and joints must be sealed beforehand:
- Large holes and joints (>5mm): seal with 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, allowing a single operator to apply up to 300 m² per day.
- For small projects, such as private houses, Passive Purple Brush can be applied using a flat paintbrush.
- Wall-to-ceiling connections must also be made airtight, especially where different construction materials meet, such as brick to concrete or steel to concrete.
- Different construction materials react differently to changes in humidity and temperature and move at different rates. This can cause small cracks in finishes, leading to air leaks, reduced energy performance, and an increased risk of damp and mould.
- Both airtight paints can be used for wall-to-ceiling connections: Passive Purple spray-applied and Passive Purple Brush.
- Get in touch with our team at info@intelligentmembranes.com to learn more.
Note: If you do not have an airless sprayer but still wish to install Passive Purple yourself, a roller-applied version is also available. It may take a little longer, but it still delivers reliable airtight performance.
Related Guides
Helpful guides related to this product:
Shipping & returns summary
Shipping & returns summary
We, at Intelligent Membranes, would like you to be 100% satisfied with your purchase and our service. In the unfortunate event of any item being unsuitable or wrong, please read the following for advice on returning goods to us.
For architects and specifiers
How to specify this product
The NBS clauses and Uniclass codes this product is specified under, with clause wording you can paste straight into your specification.
NBS clauses
- P10/310Air and vapour control layer
- P10/60Air and vapour control layer
- H92/780Air and vapour control layer
Uniclass 2015
- Pr_25_57_65_60Plastics sheets
Clause wording
AIR AND VAPOUR CONTROL LAYER Manufacturer: Intelligent Membranes Ltd, Cambridge. Tel 01223 208174. intelligentmembranes.com Product reference: Passive Purple® liquid-applied airtight vapour control membrane, spray/roller grade, with Passive Purple Brush for joints, junctions and penetrations. Certification: BBA certified. Passivhaus Institute certified component. Reaction to fire: Class C to EN 13501-1. Substrates: Concrete, brick and blockwork, timber/OSB, plasterboard and cement board, prepared and primed as recommended by the manufacturer. Detailing: Passive Purple Brush applied first to joints, junctions, frames and service penetrations in a 100 mm band (150 mm on rough masonry and high-movement joints). Field coats: Two coats to a minimum total consumption of 0.8–1.0 kg/m² on boards and 1.2–1.4 kg/m² on brick/blockwork. Plastering/dry lining over: Apply Supergrip primer over the cured membrane before plaster or dot-and-dab. Installation: In accordance with the manufacturer's current technical data sheet and installation guide. Testing: Verify airtightness by pressure test on completion.
Check against the current technical data sheet before issue. Certificates are in the Downloads tab.
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