Full-surface bonding of a waterproofing layer on top of PIR insulation is only permitted in the roof field when no torching technique is used for the application. In practice, a two-layer bituminous system is typically installed with partial adhesion to allow vapour pressure distribution, since the top layer is usually applied using a torch-on method. Partial bonding helps prevent blistering.
For adhesive-applied systems, a fully bonded waterproofing system can be installed on top of PIR insulation — provided that compatibility and performance are confirmed by the waterproofing system manufacturer. When using contact adhesives, it is essential to allow any solvents to fully evaporate before applying the waterproofing layers.
IKO recommends using IKO enertherm MG insulation to reduce sensitivity during installation. The mineral glass fleece facing of this product is less prone to blistering than an ALU-faced board.
In upstand areas, full-surface bonding is always required — partial adhesion is not permitted in those zones.