The particularly stable and moisture-resistant AGEPAN® UDP is an insulating fiberboard panel manufactured through a dry process, with a tongue and groove profile on all four sides, which complies with EN 13171. The surface of AGEPAN® UDP is extremely robust due to its troughlike bulk density profile. The advantage is that the boards can be used on both sides. It is also entirely hydrophobic, vapour-permeable and hygroscopic, and can therefore be used as sarking board in compliance with ZVDH regulations. It is used to minimise thermal bridges in roof and wall areas with rear-ventilated cladding.