Case Study

Permavent APEX provides the ideal roofing membrane for this building in a conservation area

Natwest Bank, Witney, Oxford

A re-roofing project in a conservation area

Permavent APEX provides an air-and-vapour permeable underlay that removes the need for extra ventilation

View products used in project


Witney, Oxfordshire


To install a new roofing membrane and tiles on the Natwest building in Witney, a conservation area.

Why Permavent was chosen

Due to the location of the Natwest bank in Witney, Oxford which is a conservation area, it was important that the tiles used were designed specifically to match the aesthetic of natural slate during the completion of the roof.

Blackpool Roofing chose Permavent APEX as the membrane due to its competitive characteristics and price.

Permavent APEX is both vapour and air permeable, which means no additional ventilation needed to be installed into the roof, which would necessitate new materials and construction. This was important within the solution design for the project and Permavent APEX was the ideal membrane to use to maintain the original aesthetic of the building.

By using taped APEX installers were able to reduce the amount of waste produced also, Permavent APEX comes with unique integrated double sided tape system. This ensures that the laps of the membrane are restrained in any weather condition using a 100mm head lap and meet the BS5534 standard. This allowed for up to 25% reduction in membrane usage compared to batten lap installations.

Ben Lynden, lead on the project and a director of Blackpool Roofing said, “The APEX quality is second to none, it held strong against heavy foor traffic and will be my membrane of choice going forward.”

How Permavent Products were installed:

The original tiles were removed and Apex was installed according to Permavent’s fitting instructions, good roofing practice and compliance with BS5534 & 5250. After that, concrete tiles specially designed by Cardinal Slates to match the look of natural slate in conservation areas were installed.

Accompanying Materials

  • Permavent APEX membrane
  • Concrete tiles manufactured by Cardinal Slates


Installer: Blackpool Roofing

Merchant: Independent Site Supplies

Products Used

Permavent APEX

Air Permeable Extra

  • Air and Vapour permeable membrane
  • Integrated Tape (untaped option available)
  • No need for ventilation