Skip to content

Roofing underlays

Roof underlays are essential for virtually all tile and slate pitched roof constructions, helping to protect against wind-driven rain and snow and reduce wind uplift on the roof covering. We offer one of the broadest ranges of roofing underlays available to suit a multitude of application and ventilation requirements. All of our roofing underlays are watertight, offer excellent water resistance and some of the best wind uplift performance ratings on the market.

Air & Vapour Permeable Underlays

Our vapour permeable and air open underlays feature meltblown technology within the membrane core to allow ventilation into the roofspace through the material, and vapour to escape – controlling the risk of condensation. Whilst specifying an air-permeable underlay may involve a higher initial cost, there is usually no additional need to ventilate – which saves time and labour on installation. We can work with you to determine the exact needs of your project and advise on exceptions and extra considerations, such as hydrophobically treated underlays.

Vapour Impermeable Underlays

Vapour impermeable or high resistance (type HR) membranes prevent the diffusion of water travelling through the material. Cost-effective and a great improvement on type 1F felts, these underlays will require additional ventilation for both cold and warm roofs – luckily our team can advise on the best solution for any project.

Vapour Permeable Underlays

Vapour permeable or low-resistance (type LR) underlay is airtight, but allows water vapour to disperse into the atmosphere. Where used in a cold roof solution, this type of underlay should be used in conjunction with high-level ventilation through tile or ridge vents. Where the loft space is used as living space, this type of underlay offers an ideal solution, with no additional ventilation needed providing the ceiling is well-sealed and a vapour control layer is in place.

Talk to us

Contact us today to discover more about our extensive range of building product solutions and the technical support services we can offer.

Get in touch

Glidevale Protect is a division of Building Product Design Ltd.

Other subsidiaries include ventilation systems specialist Passivent and Kingfisher Louvres, manufacturer of aluminium louvres systems.

Important Notice

Please be vigilant of fraud/cyber crime. If you receive an email from our parent company Building Product Design Ltd, please check that the email address from the sender ends in '' and any phone number given is 0161 905 5700.

If you receive any emails ending in '' or '', these are NOT legitimate, and you should contact us as soon as possible at

Site by Harris