Detailing External Junctions with a Fire-Rated Brush Membrane
On an external wall, the airtight and weatherproof layer has to survive driving rain, UV and movement — and the junctions are where it’s most exposed. Detailing them by hand needs a membrane built for the outside.
Why external junctions are critical
External corners, reveals, parapets and penetrations are too fiddly to spray neatly, yet they’re the first place wind-driven rain and air find a way in if left poorly sealed. On a fire-rated facade build-up, the detailing also has to maintain the fire performance — so the brush product needs to match the system.
The solution: Passive Purple External Brush
Passive Purple External Brush (5kg) is a fibre-reinforced, brush-applied facade membrane that is airtight, weatherproof and vapour-open. It spans gaps and seals external junctions by hand, complementing the sprayed external membrane on the open areas — keeping the whole envelope continuous.
How it is applied
- Prepare and prime the substrate as needed
- Work the membrane into corners, reveals and around penetrations
- Tie the detail into the main sprayed external membrane
Benefits
- Airtight, weatherproof and vapour-open
- Fibre-reinforced for gap-spanning
- Brush-applied for external detailing
Frequently asked questions
Vapour-open and weatherproof — how? It resists liquid water from outside while letting water vapour escape, so walls don’t trap moisture.
Can it be left exposed? Check the system spec; it’s designed for external use within the facade build-up.
Specifying a whole facade? See the airtight paint range or talk to us.