On the lower UP-I profile, TRI-ROOF+ special adhesive for ridge sheets is applied as an 8mm string over the entire rail width. The rail section to be connected is pressed into the adhesive and screwed from the top by means of a flat connector, 2 sliding nuts M10 and 2 hexagonal nuts M10 x 25 A2. If this is not possible because there is a SafeClick on the joint, the flat connector may also be connected laterally or on the bottom in the grooves by means of hammerhead screws M10 x 20 A2 and self-locking nuts M10 A2. In case of system depths greater than 12m, the UP-I joint is pushed together to 5mm, the 8mm adhesive string is applied, and the flat connector is fastened only on the lower UP-I rail to minimize the stresses due to temperature changes. If, in this type of joint, there is a SafeClick on the UP-I profile, the flat connector is fastened on the underside of the upper UP-I profile.