The OPTIM-R Roofing System is perfect for projects that require the
lowest U-value or the thinnest roof build-up. It is ideal for where
there is little space for installing new roof insulation, for example
buildings with planning height restrictions.
The System comprises vacuum insulation panels (VIPs) and PIR infill
boards. The infill boards can be cut to fit around problem areas such as roof lights, ventilator kerbs or drainage gutters.

For more information and latest documents refer to this link.