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FAQ

Roofing Membranes

Yes. Roofing membranes should comply with the relevant British Standards to help meet UK Building Regulations.
Our MultiVap Plus and MultiVap Super membranes are tested to BS EN 13859-1, achieving UKCA and CE certification. They also support compliance with:
  • BS 5250:2021 – Management of moisture in buildings
  • BS 5534:2018 – Slating and tiling for pitched roofs and vertical cladding

 

Roofing membranes are designed to provide temporary weather protection during construction. However, they should not be left exposed for longer than the period specified in the installation instructions, as prolonged exposure to UV light and the elements can affect performance. Always install the final roof covering as soon as practicable which is advised to be no more than 12 weeks, in accordance with STA Advice Note 18.

 

Vapour permeable roofing membranes are commonly used in modern pitched roof construction because they allow water vapour to escape from the roof structure while preventing the ingress of wind-driven rain and snow. This helps reduce the risk of condensation and contributes to a healthier, more durable roof system. The correct membrane should always be selected based on the roof design and in accordance with the relevant British Standards.
 

The correct membrane depends on your project's wind zone requirements, as defined by BS 5534.
  • MultiVap Plus – Suitable for Wind Zones 1–3 (150gsm)
  • MultiVap Super – Suitable for Wind Zones 1–4 (170gsm)
For more information and technical specifications, visit our Roofing Membranes product page 
 

For help with installation please head to our Membrane Brand page.

UKCA and CE markings demonstrate that a product has been tested and assessed against the applicable performance requirements. For roofing membranes, this includes testing to BS EN 13859-1, giving specifiers, contractors, and homeowners confidence that the product meets recognised quality and performance standards.
 

A roofing membrane, also known as an underlay, is an essential part of a pitched roof system. Installed beneath the roof covering, it provides temporary weather protection during construction and acts as a secondary barrier against wind-driven rain, snow and dust once the roof is complete. Roofing membranes also help manage moisture by allowing water vapour to escape, reducing the risk of condensation within the roof structure. They also help control wind pressures beneath the roof covering, contributing to the overall performance and security of slates and tiles.

 

BS EN 13859-1 is the European Standard for flexible sheets used as roofing underlays. It specifies the performance requirements and test methods for roofing membranes, including:
  • Tensile strength
  • Nail tear resistance
  • Resistance to water penetration
  • Water vapour permeability
  • Flexibility at low temperatures
  • Reaction to fire

Testing to BS EN 13859-1 supports UKCA and CE certification and provides confidence that the membrane has been independently assessed for key performance characteristics.
 

Both membranes provide excellent weather protection and vapour permeability, but MultiVap Super is our premium-performance option.
Compared with MultiVap Plus, MultiVap Super:
  • Has a heavier 170gsm construction (vs. 150gsm)
  • Offers enhanced durability and strength
  • Provides improved wind uplift performance
  • Is suitable for Wind Zones 1–4, compared to Wind Zones 1–3 for MultiVap Plus

Ubbink do not offer a warranty for the roofing membrane range. However, they are designed to last the lifetime on the roof. Assuming they are fitted as per manufacturers fixing instructions and covered within 12 weeks.
 

Wind zones identify the level of wind exposure a roof is likely to experience in different parts of the UK. Under BS 5534, roofing membranes must be suitable for the wind zone in which they are being installed to help ensure the roof performs as intended.
At Ubbink:
  • MultiVap Plus (150gsm) is suitable for Wind Zones 1–3
  • MultiVap Super (170gsm) is suitable for Wind Zones 1–4
Selecting the correct membrane for the wind zone helps improve roof performance and ensures compliance with the relevant standards.