Permavent NB 145 is a vapour-impermeable roofing underlay suitable for use in pitched roof applications. It is designed to form an airtight layer within the building envelope.
The membrane provides superior resistance to external moisture with a W1 water resistance classification.
Permavent NB 145 is available with an integrated tape system, enabling sealed overlaps to support airtightness, improve installation efficiency, and reduce material waste on site.

• Vapour-impermeable membrane for roof constructions.
• Suitable for use with all types of solar panels.
• NB 145 meets underlay recommendations in BS 5534:2014+A2:2018. Slating and tiling for pitched roofs and vertical cladding. Code of practice.
• W1 water resistance rating for external moisture protection.
• High tear resistance, supporting integrity around fixings and penetrations.
• Integrated tape for sealed horizontal laps and reduced on-site waste.
• Also available in an untaped version.
• Available 1.0m x 45m and 1.5m x 30m roll sizes