Steel substructure:
Bolted through the bottom chord:
- Stainless steel screw with sealing washer ³ Ø 19mm
- Non-positive connection between trapezoidal steel profile and substructure
- High contact force possible to generate sufficient contact pressure of the washer with vulcanized-on neoprene seal
- Inexpensive short stainless steel screws
Screw connection through the upper belt:
- Stainless steel screw with sealing washer ³ Ø 19mm
- Sufficient contact pressure, especially for sheet thicknesses £ 0.75mm difficult to reach, partial indentations (dents) at screwing points
- If the screw connection is not tight, less water penetrates because it is outside the flow plane
- Longer stainless steel screws cost more than those for lower belt mounting.
Screw connection through the upper belt with additional calottes:
- Stainless steel screw with sealing washer ³ Ø 16mm
- Two sealing levels
- If the screw connection is not tight, less water penetrates because it is outside the flow plane
- Ideal for inexperienced fitters and unsuitable tools, as the calotte as load distributor hardly allows any indentations (dents) at screw connection points
- Greater pull-out force can be absorbed at the screwing point
- Longer stainless steel screws and calottes cost more than with lower belt attachment
Wooden substructure:
Screw connection through the upper belt:
- Stainless steel screw with sealing washer ³ Ø 19mm
- Wooden purlins change their shape and twist with fluctuations in temperature and humidity, therefore no permanently secure fastening by the bottom chord is possible.
- Sufficient contact pressure, especially for sheet thicknesses £ 0.75mm difficult to reach, partial indentations (dents) at screwing points
- If the screw connection is not tight, less water penetrates because it is outside the flow plane
Screw connection through the upper belt with additional calottes:
- Stainless steel screw with sealing washer ³ Ø 16mm
- Two sealing levels
- If the screw connection is not tight, less water penetrates because it is outside the flow plane
- Ideal for inexperienced fitters and unsuitable tools, as the calotte as load distributor hardly allows any indentations (dents) at screw connection points.
- Greater pull-out force can be absorbed at the screwing point.
- Additional calottes cost additional
EN 
DE