Microporous functional film

The core component of roof membranes is the microporous functional film – an extremely thin layer made from a stretched mixture of polymer and calcium carbonate (CaCO₃). During the extrusion process, more than one billion micropores per cm² are formed within the structure of the film.

These micropores provide the membrane with high watertightness while maintaining excellent vapour permeability, based on a capillary transport mechanism. Water vapour molecules are able to pass through the micropores of the functional film and migrate to the outside, allowing moisture to escape from the roof structure.

Structure of membranes with a microporous functional film

(three-layer membranes – layers from top to bottom)

• PP nonwoven fabric
• Microporous functional film
• PP nonwoven fabric