Cromar Vent 3 Light Breathable Membrane

Vent3® is a high-performance, breathable underlay designed to protect pitched roofs and wall structures from the elements while letting trapped moisture escape. With a weight of 135gsm, it offers the ideal mix of strength and flexibility—robust enough to withstand handling and weather exposure, yet light enough to install quickly and easily. This mid-weight membrane is perfect for both new builds and refurbishments. It helps prevent water ingress while allowing internal moisture to evaporate, reducing the risk of condensation build-up within the roof structure. Whether you're working on a domestic home or a commercial site, Vent3® ensures a drier, healthier roof space all year round. It’s a reliable, long-lasting choice for roofers who need breathable protection that performs just as well in wet winter conditions as it does in the summer heat.

Available Sizes

1m x 50m roll – great for smaller or more detailed roof areas 1.5m x 50m roll – ideal for covering large surfaces quickly

FAQs – Vent3® Breathable Underlay

Can Vent3® be used as a temporary roof covering?

Yes, Vent3® is durable enough to offer short-term protection during construction. However, it should always be finished with proper roof coverings as soon as possible.

Is this underlay suitable for cold and warm roof designs?

Absolutely. Vent3® is compatible with both cold and warm pitched roof systems, making it a flexible option for a variety of projects.

Do I need to tape the overlaps?

Taping is not always essential, but it’s recommended in exposed or windy areas to improve resistance against wind-driven rain and to enhance airtightness.