Vapour Control Membranes
Advanced vapour control layers for high-performance building envelopes
Engineered vapour control membranes designed to manage moisture, improve energy efficiency and extend building lifespan across diverse climates
Engineered moisture control for durable building performance.
Moisture management is critical to long-term building performance. Poor vapour control can lead to condensation, mould growth, reduced insulation efficiency and structural damage.
Walki’s vapour control layer (VCL) solutions are designed to regulate water vapour movement with precision, ensuring optimal indoor climate, improved airtightness and long-lasting structures.
Our portfolio includes:
- Paper-based vapour control layers for reduced material impact
- Fixed Sd membranes for predictable, regulation-driven performance
- Hygro-variable solutions that adapt to changing humidity conditions
All solutions are developed for modern construction systems, supporting energy-efficient and durable buildings.
Product overview
Walki®Wall Eco VCL
Fibre-based vapour control solution
Paper-based vapour control layers designed to direct vapour flow while reducing reliance on fossil-based materials.
Available in fixed Sd and hygro-variable versions.
Best for: sustainable construction, timber frames, low-impact building systems
Walki®Wall Sd & Walki®Wall Sd PRO
Precise vapour control with fixed Sd
High-performance vapour control layers with defined, stable Sd values for consistent moisture control.
Best for: standardised construction, compliance-driven projects, predictable climate conditions
Walki®Active
Walki®Active Pro
Adaptive hygro-variable vapour control membrane
Smart hygro-variable vapour control membranes that adapt to humidity levels, enabling drying in both directions.
Best for: complex structures, renovation, timber construction, risk-prone moisture environments
| Feature | Walki®Wall Eco VCL | Walki®Wall Sd / Sd PRO | Walki®Active / Active Pro |
|---|---|---|---|
| Material base | Paper-based | PP-based / paper-based options | PP / paper-based options |
| Vapour control | Fixed / variable | Fixed | Hygro-variable |
| Sd range | 20–90 m (fixed Sd versions) 0.37–47 m (Variable version) | Sd 2 Sd 100 | 0.37–60 m Range under varying humidity conditions |
| Moisture responsiveness | Medium (fixed Sd versions) Very high (Variable version) | Medium | Very high |
| Sustainability profile | High | Standard | Standard |
| Strength improvement | Limited | Optional | Optional |
| Fire class option | Class-E available | Class-E | Class-E |
Membranes for safer buildings, inside and out
A complete A2 fire-retardant membrane system for moisture control, airtightness and fire safety
Safe buildings require balanced moisture control, airtightness and fire performance. Walki’s A2 fire-retardant membranes provide a complete solution for both the inside and outside of the building envelope.
Together, they regulate vapour flow, protect insulation and enable structures to dry properly, improving durability and energy efficiency while meeting strict fire safety requirements.
Who is
it for
Walki vapour control layers are designed for:
Construction companies and contractors
Building system providers
Insulation manufacturers
Architects and specifiers
Building material distributors
Customisation capabilities
Walki offers extensive flexibility to meet specific building requirements:
- Tailored Sd values based on regional regulations
- Choice of barrier type (fixed or hygro-variable)
- Reinforced structures for blown-in insulation applications
- Optimised printability and branding options
- Custom roll sizes and formats
- Performance tuning for airtightness, durability and installation efficiency
Sustainability
focus
Walki vapour control layers contribute to:
- Extended building lifespan
- Reduced risk of structural damage
- Improved insulation performance
- Lower operational energy demand
The Walki®Wall Eco range further supports sustainability goals by incorporating fibre-based materials while maintaining required barrier performance.
What makes Walki vapour control layer solutions different
Material innovation
Paper-based alternatives reduce dependency on traditional nonwoven plastics without compromising performance.
Climate-adapted performance
Solutions designed to meet country-specific Sd requirements across Europe.
Smart moisture management
Hygro-variable membranes enable bi-directional drying, reducing moisture risk.
Industrial scalability
Reliable supply and consistent quality for large-scale construction projects.
Proven standards
CE-marked according to EN 13984 and compliant with major VOC standards.
Lower carbon membranes for construction
Paper-based vapour control layers reducing material impact
The construction sector accounts for a significant share of global CO₂ emissions, making material choices more important than ever. Walki’s paper-based vapour control layers replace fossil-based nonwoven materials with fibre-based alternatives, helping reduce the carbon footprint without compromising performance.
This innovation supports energy-efficient buildings while aligning with increasing demand for EPDs and more sustainable construction solutions.
“Raw materials account for up to 95% of a membrane’s carbon footprint. By switching to paper-based layers, we can significantly reduce the overall impact.”
Juho Hyytiäinen
Business Line Manager, Construction
Performance comparison
| Criteria | Walki VCLs | Standard PE-VCLs | No VCL |
|---|---|---|---|
| Moisture control | Excellent | Moderate | Poor |
| Energy efficiency | High | High | Low |
| Risk of mould | Very low | Medium | High |
| Drying capability | High (Active) | Low | Uncontrolled |
| Sustainability options | Available | Limited | N/A |
| Airtightness | High | High | Low |
| A2 fire classification | Available | No | N/A |
A vapour control layer regulates the movement of water vapour through walls and ceilings to prevent condensation and improve building durability.
They are ideal in structures where moisture conditions vary, such as timber frames or renovation projects.
Sd value indicates vapour resistance. Higher Sd means stronger vapour barrier performance.
It prevents moisture accumulation, protecting insulation performance and avoiding mould or structural damage.
Yes, modern paper-based VCLs provide reliable performance while offering a reduced material impact compared to conventional alternatives.
Not sure which vapour control layer fits your project?
Our experts help you select the right membrane based on climate, structure and performance requirements. From standard Sd solutions to smart hygro-variable systems, we support your project from design to delivery.
