Walki®Roof Mono
Monolithic roofing underlay engineered for durability and breathable performance
High-performance monolithic roofing underlay for long-lasting, airtight
and vapour-open roof structures
Reliable Class-W1 protection. Long-term breathability. Built for demanding roofs.
Walki®Roof Mono is a next-generation roofing underlay membrane designed for modern pitched roof constructions. Built on advanced monolithic technology, it delivers Class W1 water tightness combined with high vapour permeability, ensuring effective moisture management without compromising durability.
Unlike traditional microporous membranes, Walki®Roof Mono maintains its structural integrity over time, even under challenging temperature conditions and prolonged exposure. It supports energy-efficient building envelopes by acting as a windproof and airtight layer, helping to reduce uncontrolled airflow and heat loss.
Engineered for reliability, the membrane is suitable for installation under dark roofing materials, low-pitch roofs from 10°, and even beneath solar panel systems.
Product overview
Structure: Nonwoven PP / monolithic functional layer / nonwoven PP
Key performance highlights:
- Water penetration resistance: Class W1
- Vapour permeability: Sd ~0.07 m (highly breathable)
- Airtight and windproof performance
- UV resistance: up to 3 months outdoor exposure
- Temperature resistance: up to 70–80°C
- Compliant with EN 13859-1
- Fire classification: Euroclass E
Application areas:
- Pitched roofs ≥10°
- Under tiles, especially dark roofing materials
- Roofs with solar panel installations
- Direct installation on insulation or wooden decking
Why monolithic technology matters
Durable performance beyond microporous membranes
Traditional microporous membranes rely on tiny pores that can clog over time due to dust, oils or surfactants. Walki®Roof Mono uses a continuous monolithic functional layer, allowing vapour diffusion through molecular transport rather than pores.
What this means for your project:
- Improved long-term reliability in real conditions
- Consistent breathability over time
- Higher resistance to ageing and contamination
Who is
it for
Built for professionals across the construction value chain Walki®Roof Mono is specified and used by:
Roofing contractors and installers
House builders and construction companies
Architects and specifiers
Building material distributors
Prefabricated housing manufacturers
Customisation capabilities
Designed to meet local standards and project-specific needs
Walki offers extensive flexibility to match regional requirements and performance targets:
- Adjustable basis weight and mechanical strength
- Tailored vapour transmission levels
- Custom roll sizes and formats
- Integrated self-adhesive strips
- Branding and printability options
- Optimised performance for different climates
Performance & durability benefits
Designed for real-world conditions
- Maintains class-W1 classification even after artificial ageing
- Resistant to UV, heat, humidity and chemicals
- Withstands oils and wood preservatives
- Prevents condensation and mould formation
- Elastic and mechanically robust for safe installation
- Passes “step-through” resistance requirements
Supporting lower-impact construction
The construction sector accounts for a significant share of global emissions. Walki supports the transition towards more efficient buildings by improving airtightness and moisture control, reducing energy losses over time.
Additionally, Walki is actively developing lower carbon material alternatives, including fibre-based solutions for interior membrane layers, helping reduce the overall environmental footprint of construction systems.
Walki roofing underlay vs alternatives
| Criteria | Walki®Roof Mono | Standard Microporous | No Underlay |
|---|---|---|---|
| Resistant to water penetration | Class-W1 | Class-W1, potentially reducing to class-W2 over time if degraded | None |
| Breathability | High & stable | High, increases further if degraded | Yes |
| Airtightness | Yes | Yes | No |
| Durability | Very high | Moderate | N/A |
| Energy efficiency | High | Medium | Poor |
| Condensation control | Excellent | Excellent | Poor |
A reliable choice for durable, breathable and energy-efficient roofing systems.
A monolithic membrane uses a continuous functional layer that allows vapour diffusion without pores, ensuring long-term breathable performance and durability.
W1 is the highest class of water resistance under EN 13859-1, ensuring reliable protection against rain penetration.
Yes, it is designed to withstand elevated temperatures and is suitable for installations under solar systems.
By acting as an airtight and windproof layer, it reduces heat loss caused by uncontrolled air movement within the roof structure.
Yes, it can be used on pitched roofs starting from 10°, making it suitable for a wide range of designs.
Build roofs that last longer
Discover how Walki®Roof Mono can improve durability, energy efficiency and installation reliability in your next project.
