Permavent Ltd

About Permavent

Permavent is a UK manufacturer of high-performance roofing underlays, walling membranes and low-pitch roofing systems, with more than 20 years’ experience across new-build and refurbishment projects.

Working across residential, social housing, commercial and heritage construction, Permavent supports architects, specifiers, housebuilders and contractors in designing robust, compliant building-envelope solutions.

Our approach extends beyond individual products. Permavent considers how every component works together to manage moisture, protect the structure and support the long-term performance of the roof or wall.

Technical and specification support

Permavent provides technical support throughout the design, specification and installation process.

Our nationwide specification and technical teams work directly with architects, housebuilders, contractors and designers to develop project-specific solutions in accordance with relevant guidance, including BS 5534, BS 5250 and NHBC Standards.

Support includes advice on:

• Roof and wall build-ups
• Condensation risk and moisture management
• Ventilation strategies
• Underlay selection and wind-uplift requirements
• Low-pitch roof design
• Installation best practice

Early technical involvement helps identify potential risks, avoid specification conflicts and reduce costly changes on site. This is particularly valuable on refurbishment and heritage projects, where existing structures and restricted roof pitches can create more complex design challenges.

As buildings become more insulated and airtight, effective moisture management is increasingly important. A clear, considered specification helps ensure that the proposed system remains compliant and performs as intended throughout the life of the building.

Proven performance at scale

Permavent products are used across the UK on a wide range of building types and exposure conditions.

In 2025 alone, more than 25 million square metres of Permavent roofing underlay was installed.

This scale of use reflects the confidence placed in Permavent by contractors, developers and specifiers across both new-build and re-roofing applications.

Independent testing and certification

Permavent products are independently tested, with relevant products supported by UKCA and CE marking and BBA certification.

Testing assesses important performance characteristics, including:

• Wind-uplift resistance
• Resistance to water penetration
• Tensile strength
• Nail-tear resistance
• Water-vapour permeability
• Resistance to ageing

For walling membranes, reaction to fire, thermal performance and mechanical durability are also key considerations.

Independent testing and certification provide specifiers with clear performance data and confidence that products are suitable for their intended applications.

Moisture management

Moisture management is central to Permavent’s product development. If moisture is not properly controlled, it can contribute to condensation, mould growth, timber decay and reduced thermal performance.

Permavent roofing underlays are designed to provide secondary protection against wind-driven rain and snow while supporting the controlled movement of water vapour through the roof build-up.

Air-open and vapour-permeable underlays can support compliant roof designs and, in suitable applications, may reduce or remove the need for additional roof-space ventilation. This depends on the complete roof build-up, the conditions of certification and compliance with BS 5250.

Permavent’s walling range includes breather membranes and air and vapour control layers designed to manage moisture and air movement through the wall build-up, helping protect the structure and maintain thermal performance.

Product solutions

The Permavent range includes:

• Air-open and vapour-permeable roofing underlays
• Walling breather membranes
• Air and vapour control layers
• Fire-rated walling membranes
• Low-pitch roofing systems
• Dry-fix and roof ventilation products
• Lead-replacement systems

Together, these products address moisture control, airtightness, weather protection and long-term building-envelope performance.

Low-pitch roofing systems

Permavent’s Easy Roof System enables natural slate and other pitched-roof coverings to be installed below their conventional minimum pitch while maintaining a weathertight roof construction.

By managing water beneath the primary roof covering, the system provides greater design flexibility without compromising the external appearance of the roof.

The independently tested system received the Queen’s Award for Innovation in 2014, reflecting Permavent’s approach to solving practical roofing challenges through engineered system design.

Long-term performance

Sustainability is not only about material selection; it is also about how well a building performs throughout its lifetime.

Durable, well-designed roofs and walls can reduce maintenance, protect structural components and extend the service life of a building. Through effective moisture management, independently tested products and considered system design, Permavent helps create building envelopes that perform reliably over the long term.

A trusted technical partner

With more than 20 years of technical expertise, nationwide specification support and products proven across millions of square metres of roofing, Permavent has established itself as a trusted partner to the UK construction industry.

Our focus is clear: to provide compliant, practical and dependable roofing and walling solutions, from early-stage design and specification through to installation on site.