Photovoltaic mounting systems and substructures
The substructure forms the fundamental framework of a photovoltaic system and ensures the secure, permanent attachment of the solar modules on different types of roofs or open spaces. A well-thought-out mounting system is the basis for a long-lasting and efficient photovoltaic system that can withstand the diverse environmental influences for decades. The individual components must be perfectly coordinated with one another to ensure maximum safety.
Roof hooks
Roof hooks are the primary connecting elements between the roof structure and the mounting system for tiled roofs. They are made of high-quality stainless steel or galvanized steel and must withstand extreme loads. They are mounted directly on the roof rafters, with the hook gripping under the roof tile. The dimensions and spacing of the roof hooks depend on the expected snow and wind loads as well as the weight of the modules. Modern roof hooks often have height adjustment options to compensate for unevenness in the roof and ensure optimal load distribution. More about roof hooks...
Wood screws
Special wood screws are used to attach roof hooks to the rafters. These must have building approval and are usually made of hardened stainless steel. The screws have a diameter of 6 to 8 millimeters and are available in lengths of up to 300 millimeters. An optimized thread and special drill bits reduce the screwing torque and prevent the wood from splitting. More about wood screws...
Base rails
The base rail is the primary basic element in flat roof systems. It is either mechanically attached or weighted down with ballast and forms the basis for further adjustments. The rails have special profiles to accommodate connecting elements and module supports. The alignment of the base rails determines the subsequent module alignment and must be taken into account during planning.
Triangular supports
Triangular supports enable modules to be mounted on flat roofs or in open-space systems. They determine the installation angle of the modules and thus their energy yield. The construction must withstand considerable wind and snow loads and is usually made of aluminum. Various angle settings enable optimal adaptation to local conditions.
Profile rails
Profile rails or mounting rails form the supporting framework of the substructure. They are made of high-quality aluminum and are available in various profile thicknesses. The rails have special functional chambers for accommodating connecting elements and cable routing. Anodizing protects against corrosion and ensures decades of durability. The dimensions of the rails depend on the spans and expected loads. More about profile rails...
Rail connectors
Rail connectors are used to extend the mounting profiles and must have the same stability as the rails themselves. They are designed as internal connectors and inserted into the profile chambers. The connection is made using special screw connections that prevent slipping. The connectors must be able to safely absorb the tensile and compressive forces that occur.
Cross connectors
Cross connectors enable the connection of intersecting mounting rails in multi-layer systems. They must be able to absorb both vertical and horizontal forces and are usually fastened with self-locking hammer head screws. The connection must be free of play and must not come loose even under load.
Middle clamps
Middle clamps fix two adjacent modules to the module frame. Some have EPDM inserts that ensure secure clamping and at the same time protect the module frame from damage. The clamping height must be precisely tailored to the modules used. Modern systems have quick assembly systems and integrated grounding tips. More about Middle clamps...
End clamps
End clamps secure the outer modules of a module row. They must withstand particularly high wind loads and are also equipped with EPDM inserts. The design of the end clamps is also aesthetically important, as they shape the external appearance of the system. As with the middle clamps, exact coordination with the module frame height is essential. More about end clamps...
Wind deflectors
Wind deflectors reduce the wind loads on the modules by directing the air flow in a targeted manner. They are made of weather-resistant aluminum and must be aerodynamically optimized. The effectiveness is proven by wind tunnel tests. Integration into the mounting enables efficient assembly and maximum effectiveness.
Ballasting trays
Ballasting trays hold the required ballast in flat roof systems. They are made of UV-resistant plastic or aluminum and must be able to safely support the weight of the ballast. The shape of the trays is designed to ensure even load distribution. Integrated drainage openings prevent water from accumulating.
Grounding terminals
Grounding terminals establish the electrical contact between the module frames and the substructure. They must ensure a permanently low contact resistance and be corrosion-resistant. The connection is made using special contact elements that dig into the metal surfaces when the clamp is tightened.
Cable duct
Cable ducts protect the electrical wiring from UV radiation and mechanical stress. They are usually made from UV-resistant plastic and must take the thermal expansion of the cables into account. Integrated fastening points enable secure installation on the substructure. The dimensioning depends on the number and cross-section of the cables to be routed.
Cable clamps
Cable clamps fix the string and connection cables to the substructure. They prevent the cables from sagging and protect against mechanical stress. The clamps must be UV-resistant and must not damage the cable insulation. A strain relief function prevents the cables from slipping out.
End rails
End rails form the clean end of module fields and at the same time protect the module edges. They are made of aluminum and must be weatherproof. The profiles are designed so that they blend harmoniously into the overall appearance of the system. Integrated drainage channels drain rainwater away in a targeted manner.
The professional planning and installation of all components is crucial for the long-term safety of the entire photovoltaic system. Professional planning begins with a detailed analysis of the installation location, including a thorough examination of the static conditions and local wind loads. Particular attention must be paid to the compatibility of all materials used in order to avoid contact corrosion. The use of high-quality stainless steel screws and compliance with the prescribed tightening torques are just as important as the correct alignment of all components.
The building physics aspects play a central role in the installation. The thermal expansion of the various materials must be taken into account by means of appropriate expansion joints in order to avoid tensions in the structure. When penetrating the roof skin or facade, special care must be taken to ensure the permanent tightness of the building. The integration of penetrations into the existing drainage concept must be taken into account, as must lightning protection and electrical safety.
An often underestimated aspect is the regular maintenance and inspection of the system. All fastening points must be checked at set intervals to ensure they are firmly in place. The sealing elements must also be checked and replaced if necessary. Checking the electrical connections and the potential equalization is just as important as visually checking for corrosion damage or material fatigue. Only through these regular inspections can trouble-free operation be guaranteed over the entire service life of 20-30 years.
The documentation of all components and maintenance work in a system pass enables the seamless tracking of all measures and facilitates future service operations. In addition to the technical data sheets, this should also contain photos of the installation and test reports. Compliance with all relevant standards and guidelines must be consistently guaranteed and documented in order to have a legally secure basis in the event of damage or warranty claims.