The GRUVER element consists of glass fibre mat with 119 holes per sq.m. and a diameter of 4 cm covered with a high quality polypropylene polymer and bitumen compound especially formulated for use with all types of APP or SBS modified bituminous membranes.
Only 14% of the GRUVER is not covered by holes and this is the area which adheres to the overlying waterproofing layer ensuring uniform partial bonding of the waterproofing membrane on the deck.
Smooth top and bottom finish is torched off in polyethylene film.
For all applications requiring partially bonded waterproofing membranes and vapour barrier. Partial bonding allows the water vapour to flow in the loose laid areas through to the breather vents.
The best way to protect the waterproofing system from shrinkage due to minor structural movements, is to space the anchoring points evenly. Treat the laying surface with a bituminous primer then dry lay the GRUVER. The first torched-on waterproofing layer bonds to the laying surface exclusively through the holes.
Casali Gruver - Tech Data Sheet