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.

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

Seamless coverage - Sprays around brackets, junctions, and fixings where tapes can’t reach. Adheres to multiple materials - Bonds to steel, boards, concrete, and insulation interfaces. Flexible and crack-bridging - Moves with the frame without compromising the seal. Exceptional airtightness - Achieves below 0.6 ACH with correct detailing. Fast application - Large areas can be sprayed quickly, reducing installation time. Sustainable choice - Water-based, low VOC, and supports energy-efficient design.

  • Ventilated
    roof space

  • Intermediate
    floor

  • Window
    head & sill

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.

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

Perfect adhesion to timber surfaces - bonds strongly to OSB, ply, and sheathing boards. Seamless and flexible - covers complex junctions, corners, and penetrations effortlessly. Exceptional airtightness - tested and proven to achieve <0.6 ACH. Vapour control built in - helps regulate internal humidity and prevent condensation. Fast and easy application - applied by airless spray or roller, drying to a tough, flexible film. Eco-aligned - water-based, VOC-free, and compatible with sustainable timber frame systems.

  • Timber floor

  • Party wall

  • Intermediate floor

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