The installation of a photovoltaic substructure on trapezoidal sheet metal roofs is one of the simplest and most cost-effective options when constructing a photovoltaic system.
Nevertheless, there are a few important points that must be observed to ensure professional installation.
In principle, it is possible to work with continuous mounting profiles, similar to those used for tiled roofs, which are installed across the entire width of the photovoltaic system.
In practice, however, the more efficient method is usually preferred: the use of short rails that are bolted from high bead to high bead.
This approach not only saves considerable material costs, but also enables faster assembly. At the same time, structural safety is fully maintained – in some cases, this construction method even makes it easier to provide structural verification.
Installation of short trapezoidal rails from bead to bead
The most common method of installation on trapezoidal sheets is to fasten them with short trapezoidal rail sections from bead to bead. Each trapezoidal sheet has high and low ribs. With this installation technique, the trapezoidal rail is screwed directly onto the high rib, which ensures a particularly stable connection.
Example: Standard trapezoidal sheet metal
A typical trapezoidal sheet has a bead spacing of 33 cm. That is why we have pre-cut our short rails to a length of 40 cm. These short rails are:
- Fitted with EPDM seal (partially pre-installed) for optimum weather protection,
- 24 holes to facilitate screw connection — no pre-drilling required.
- Always in stock for fast delivery.
Custom-made products for individual requirements
Since not every trapezoidal sheet metal has the same corrugation spacing or profile, we also offer customised cuts of our trapezoidal rails. This allows you to adapt your substructure to your specific sheet metal profile with millimetre precision.
It all depends on the right screw!
Depending on the material (steel or aluminium) and sheet thickness, we offer you the most suitable screws for your assembly requirements.
Self-drilling screws
Our self-tapping screws with EPDM sealing washers and building authority approval feature a robust bi-metal drill tip and a drilling capacity of 3 mm. They are ideal for fastening our trapezoidal rails to:
- Steel trapezoidal sheet metal with a thickness of 0.63 mm or more,
- Aluminium sheet with a thickness of 0.50 mm or more.
For optimum sealing, there is an additional EPDM sealing washer under the screw head, which ensures a weatherproof and durable connection.
Thin sheet metal self-tapping screws with EPDM sealing washer
Our thin sheet metal drill screws with building authority approval are also equipped with a bi-metal drill tip and are particularly suitable for screwing into thinner sheets with a thickness of 0.50 mm or more.
Special features:
- When screwed in, they slightly bulge the sheet metal, thus ensuring a secure fit without chip formation.
- An additional EPDM sealing washer under the screw head improves the seal and protects against moisture ingress.
Facade drill screws
The use of façade drill screws for fastening short trapezoidal rails is rather unusual. These screws are designed to be screwed directly through the trapezoidal sheet metal into the substructure.
Our range includes façade drill screws for:
This means we can offer you the right solution even for special requirements.
Short rails in many variants
For mounting short trapezoidal rails from high bead to high bead, we offer three different mounting rails in various heights:
Flat trapezoidal rail
Total height 1.60 cm
Medium trapezoidal rail Total height 2.50 cm
High trapezoidal rail Total height 6.00 cm
Our standard version
All variants are available in 40 cm long pieces as standard. We also offer the following practical options:
- Optionally fully covered with EPDM sealant for improved weather protection or as a sealant.
- Pre-drilled 24 times, allowing direct screw connection to the trapezoidal sheet metal roof without pre-drilling.
Thanks to our stock availability, we can fulfil your orders quickly and reliably.
We are also happy to cut your trapezoidal rails to size – precisely tailored to the corrugation spacing of your trapezoidal sheet metal.
This gives you a perfectly matched substructure that enables quick and secure installation.
Installation parallel to the high bead – for modules lying crosswise
In addition to our short trapezoidal rails for screwing from bead to bead, we offer you another option for mounting on trapezoidal sheets.
Special high-bead rails are used for this purpose, which are fastened parallel to the high bead. This mounting solution is particularly suitable for the installation of transverse modules.
Our high-profile rails are:
- Pre-assembled for easy handling,
- Optionally fitted with EPDM seal for optimum weather protection or sealing.
- Prepared for direct screw connection – no pre-drilling required.
This solution enables safe and efficient installation, even with special module configurations.
Variants of our high-profile rails
Our flat high-bead rail has been specially developed for direct fastening in the direction of the high bead and is ideal for mounting transverse modules on the long side of the frame.
Technical details:
- Base width: 4 cm
- Total height: 13 mm
- With T-slot channel for flexible installation of the module mounting system
We offer the flat high-ribbed rail in two different lengths, each with the option of a factory-fitted EPDM seal for optimum weather protection.
High high-bead rail | Click system
Our high high-bead rail works with a two-part click system:
- Lower rail: is screwed directly onto the high bead,
- Upper rail: is then clicked into place at the side.
Advantages of the click system:
- Easy installation, as the top rail can be fitted without tools.
- Improved rear ventilation of the modules thanks to the raised structure,
- Increased stability and protection against weather conditions.
This system not only simplifies installation, but also ensures sustainable and efficient system ventilation.
Our Hochsicken click system in detail
Due to the very low material usage, fastening the modules with our high-bead rails is by far the most cost-effective method of installation on trapezoidal sheet metal.
You benefit not only from reduced material costs, but also from fast, efficient installation and a durable, stable construction.
Special solution for an additional inclination of 5° on trapezoidal sheet metal
A simple and effective way to achieve an additional inclination of 5° (additional elevation) for modules laid crosswise and clamped to the short side of the frame is to combine high and flat trapezoidal rails.
This is how the solution works:
- The different heights of the two trapezoidal rails automatically create an angle of inclination of approximately 5°.
- An additional angle adapter is used, which can be easily clicked into the groove channel of the rail and then securely fixed in place with a sheet metal screw.
- This ensures flush and stable installation of the modules.
Advantages of this special solution:
- Cost-effective and material-efficient,
- Simple installation without complex mounting systems,
- Optimised rear ventilation and improved yields thanks to the additional slope,
- Ideal for projects where a slight additional inclination is required for performance optimisation.
Further information on installation on trapezoidal sheet metal roofs can be found here:
We plan your PV substructure – precisely tailored to your needs!
We would be happy to take care of the planning of your PV substructure for you.
You will receive a detailed layout plan from us – including structural analysis on request – as well as a tailor-made quote.
To enable us to implement your plans in the best possible way, please complete our online enquiry form in full and attach a sketch of your desired layout (including the orientation and placement of the modules on your roof).
