Airtight White - Vapour Control, Airtight & Smoke Tight Paint (11.4kg) - Spray / Roller Applied
Airtight White - Vapour Control, Airtight & Smoke Tight Paint (11.4kg) - Spray / Roller Applied
Passive Purple Airtight White
VOC-Free Airtight, Vapour & Gas Control Membrane
Passive Purple Airtight White is a VOC-free, water-based airtight membrane providing reliable vapour control and protection against radon and methane gases — without any nasty chemicals or fumes.
Ideal for those on-site “oops” moments, it can be applied directly onto plasterboard if a vapour control layer has been missed. When used with IM Primer, it can be left on show or painted over, making it perfect for exposed environments such as car parks, museums, and stairwells.
Once dry, it forms a tough yet flexible polymer membrane that moves with the building and resists impact damage — eliminating the rips, tears, staple holes and failed tapes associated with traditional paper membranes.
Less labour. Less waste. More performance.
Check out our case study
Tested & Certified — worldwide
Airtight White is the white-pigmented version of Passive Purple — the same liquid airtight membrane formulation — independently tested to both ASTM (ICC-ES) and EN standards, so it can be specified worldwide:
- 🌿 French A+ indoor-air rating & Finnish M1 class — very low VOC emissions (EN 16516 / RTS)
- 🏠 Passive House Institute Class A airtight — 0.02 m³/h·m² @ 50 Pa (EN 12114)
- 🔒 Air barrier material — 0.02 L/s·m² at 75 Pa (ASTM E2178)
- 🔥 Reaction to fire — Class A to ASTM E84 (Flame Spread 0); Euroclass C-s1,d0 to EN 13501-1 (B-s1,d0 with FRED)
- 💧 Watertight (EN 14891) & intelligent vapour control, Sd ~0.8–40 m (EN ISO 12572)
- ☀️ High solar reflectance — the white finish reflects even more solar energy (the purple grade is independently rated SRI 52, ASTM E1980)
- 🛡️ Radon barrier — diffusion coefficient 3.3 × 10⁻¹² m²/s (ISO/TS 11665-13)
- 💨 Methane / ground-gas barrier — low permeability (ISO 15105)
- 🧱 Strong adhesion — steel 2.7, CLT 1.83, gypsum 1.6, brick 1.5 N/mm² (EN ISO 4624)
- 🧵 Flexible & crack-bridging — ~219–350% elongation (EN 12311-1)
- 🦠 10/10 mould resistance — no defacement (ASTM D3273)
- ♻️ Environmental Product Declaration (EN 15804)
- ✅ ICC-ES ESR-4715, Passivhaus certified & BBA approved
See all test data & certifications →
Related Guides
Helpful guides related to this product:
- Passive Purple & Airtight White: Tested & Certified (ASTM & EN data)
- The French A+ indoor-air rating explained
- What Is a Vapour Control Layer? | VCL Explained
- My Builder Forgot the Vapour Control Layer? Here’s How to Fix It
- Reuben College, Oxford – Award-Winning Airtight Basement with Airtight White
Quality assurance: Download the free Installation & QA Record sign-off sheet (IM-QA-03) for this product.