PASSIVE PURPLE ON LIGHT GAUGE STEEL

Light-gauge steel frame (LGSF) systems are fast, precise, and sustainable, but airtightness can be a major challenge. The multiple steel components, fixings, and junctions create countless potential leakage points. That’s where Passive Purple excels.

Passive Purple Liquid applied airtight membrane

How It Works

Passive Purple is a liquid-applied airtight and vapour control membrane that’s sprayed or rolled directly onto the internal face of the LGS wall buildup, typically over the sheathing board. Once applied, it dries to form a continuous, flexible, airtight film that fully seals all gaps, joints, and penetrations, even around complex steel connections.

Because Passive Purple is liquid-applied, it eliminates the need for tapes or membranes that are difficult to fit around the studs, screws and junctions typical of steel framing. The result is a smooth, seamless barrier that delivers exceptional airtightness and vapour control, even in areas where other systems fail.

Why Passive Purple is ideal for Light Gauge Steel

Liquid-applied and seamless, Passive Purple seals the countless junctions, fixings and penetrations that make steel frames so hard to make airtight.

  • Passive purple being used on a retrofit school project

    Seamless coverage

    Sprays around brackets, junctions and fixings where tapes can’t reach.

  • service pipe airtight paint that is brush applied to make an airtight seal

    Bonds to any substrate

    Adheres to steel, boards, concrete and insulation interfaces for a continuous seal.

  • class b fire membrane

    Below 0.6 ACH airtightness

    Delivers exceptional airtightness with correct detailing – applied fast by spray or roller.
"Finished airtight building coated with Passive Purple liquid membrane for full internal and external airtightness"

Typical Build-Up Example

  1. External cladding
  2. Sheathing board (e.g. cementitious or OSB)
  3. Passive Purple applied to internal face
  4. Insulation layer
  5. Internal lining (e.g. plasterboard)


Application Details
Apply by airless spray or roller directly to clean, dry sheathing boards. Minimum wet film thickness: 0.6mm (approx. 0.3mm dry). Seal all penetrations, joints, and interfaces for a continuous barrier. For best adhesion, ensure surfaces are free of dust, oil, or grease.

PASSIVE PURPLE ON TIMBER FRAME

Airtight Confidence for Timber Construction

Timber frame buildings are fast, sustainable, and naturally energy-efficient, but their performance depends heavily on airtightness. Every joint, board edge, and service penetration is a potential air leak if not properly sealed. That’s where Passive Purple delivers its strength.

airtight paint for joints on OSB timber frame

How It Works

Passive Purple is a liquid-applied airtight vapour control membrane designed for use on the warm side of the insulation. In timber frame builds, it’s typically applied directly over OSB or sheathing boards, forming a continuous, flexible, and seamless coating that seals every joint and
junction.
The coating fully adheres to the timber substrate, bridging gaps and imperfections that tapes or membranes can’t reliably cover. Once dry, it becomes a robust, elastic film that moves with the building, ensuring long-term airtightness without cracking or peeling.

Why Passive Purple is Ideal for Timber Frame

Applied over OSB or sheathing on the warm side of the insulation, Passive Purple forms a continuous, flexible airtight layer that moves with the timber frame.

  • paint brush applied Airtight liquid vapour control

    Perfect bond to OSB & ply

    Bonds strongly to OSB, ply and sheathing boards.

  • liquid airtight paint that is brush applied to seal wall penetrations like water pipes

    Seals every junction

    Covers complex junctions, corners and penetrations effortlessly.

  • Retrofit airtight paint – Passive Purple applied for improved energy efficiency and airtightness in existing buildings

    Vapour control built in

    Helps regulate internal humidity and prevent condensation.
airtight paint for joist ends on timber frame or masonry builds

Typical Build-Up Example

  1. External cladding
  2. Sheathing board (OSB or ply)
  3. Passive Purple airtight layer
  4. Insulation (between or over studs)
  5. Internal lining (plasterboard or finish layer)


Application Details
Apply via airless spray or long-haired roller onto clean, dry OSB or sheathing boards. Minimum wet film thickness: 0.6mm (approx. 0.3mm dry). Pay special attention to junctions, penetrations, and service zones. Allow to dry fully before applying subsequent coatings or finishes

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