Due to the longitudinally profiled roof surface of the Fiat Ducato van, it is not easy to glue on solar mounting profiles and Flat Light solar panels. There is not enough adhesive surface in the front area and there is also the risk of wind noise. This is why special "gap fillers" were developed. They are glued into the recesses with Sikaflex (included with every all-in-one system). The bracket or the Flat Light solar panel is then glued onto the continuous surface. In the rear area, this is not necessary and also not advisable as it would hinder water from running off the roof.
Gap filler set consists of 2 specially pretreated aluminium sheets. The number of sheets required depends on the panels' width and positioning.