Nuralite's first membrane sheets were laid in NZ in the early 1960s - subsequently many systems are now reaching the end of their useful life. Upgrading of these systems is relatively simple if you stick with Nuralite.
The upgrading process can use original roof as an underlay and saves disposing of the old membrane - an expensive exercise - but be wary of people who do not understand the unique characteristics of historic Nuralite sheets.
The first thing to consider is insulation. Older buildings had very little insulation and it is a cost effective time to provide additional insulation before installing a new membrane. Nuralite would recommend using Enertherm PIR Insulation Boards
which can be fastened directly onto the existing membrane. Tapered boards may be used to create a fall if there is currently ponding issues with the roof.
may be installed directly over the Nuralite sheets (or onto the Enertherm boards if they are being used). Both of these membranes will be installed with a venting system to allow the Nuralite sheets to breathe.