Can I use my usual brand of breathable membrane and still get the 40 year guarantee?

No, in order to qualify for the 40 year guarantee the following criteria must be met:
The installation must be installed as per the manufacturer’s instructions and in accordance with BS5534:2014 + A2:2018.
The specified membrane must be PERMAVENT DRY+.
The specified tape must be PERMAVENT BUTYL TAPE.
The contractor must record both in-progress and completed project images to be supplied alongside invoices at the tie of guarantee application,
Guarantee applications must be submitted no later than 1 month after project completion.
Please note each Easy Roof installation requires its own submission.

For more information and to request a guarantee click here.