When you look at a finished roof, it’s easy to forget that the tiles are only part of the system. Every well-built roof starts with a roofing membrane (often referred to as roofing felt or roof underlay) installed directly over the roof structure. This layer provides vital secondary protection against wind-driven rain, dust and moisture before the tiles are even installed.
In simple terms, a membrane for roofing acts as a safety net beneath the tiles, guiding any water that gets past the outer covering safely down to the eaves and out of the building.
A breathable roofing underlay is the first major component fitted during a new roof installation, installed before battens and tiles. Modern roofing breathable membrane products are designed to allow moisture vapour from inside the building to escape, while still acting as a waterproof membrane for roof protection from the outside.
This balance is critical. A breathable membrane for roof applications helps prevent condensation build-up within the roof space, protecting insulation, timber and structural components over the long term. Without a breathable membrane roof system in place, trapped moisture can lead to damp issues, reduced insulation performance and, in severe cases, structural damage.
That’s why breathable membranes are now considered best practice in modern roofing, particularly when used alongside correct eaves and ridge ventilation.
Metrotile UK supplies Vapr Free Xtra, a high-performance breathable roof membrane specifically designed to work seamlessly with lightweight metal roofing systems. Unlike non-breathable alternatives, this roofing membrane supports ventilation while maintaining excellent weather resistance.
Vapr Free Xtra is available in two practical roll sizes:
It’s worth noting that products such as an EPDM roof membrane are typically used for flat roofs and are not suitable as a breathable underlay beneath pitched metal roof tiles.
A high-quality breathable roofing membrane forms the foundation of a complete Metrotile roof system. Backed by a 40-year weatherproof guarantee, it provides reliable moisture control, excellent breathability and straightforward installation—helping ensure your roof performs as a durable, long-lasting system from the inside out.
