Solar panel mounting: tiled, metal and flat roofs, walls, balconies
In short: The roof determines which mounting is suitable. On tiled roofs, a roof hook beneath the tiles holds the rails in place; on standing seam metal roofs, a clamp without penetration is used; on trapezoidal sheet metal roofs, a short rail is used. On flat roofs, the modules are mounted at an angle and, for roof pitches of up to 3 degrees, are often secured using ballast alone, without the need for drilling. On balconies and walls, brackets with hooks or screws are used. A specialist contractor will assess whether the roof can support the weight and the loads from wind and snow.
Contents
Pitched roof with tiles
The mounting bracket, also known as a substructure or mounting system, connects the modules to the roof. It must support the weight of the modules and withstand wind and snow without damaging the roof covering. The parts required for this depend primarily on the type of roof covering. The product range consists largely of the mounting system from K2 Systems.
Roof hooks are used on a tiled or roof-tile roof. They are fixed to the roof’s substructure, run beneath the tiles and support the rails on the outside, to which the modules are clamped.
- Roof hooks: According to K2, the SingleHook 3S and 4S hooks cover around 80 per cent of applications; the range also includes SolidHook and hooks for slate.
- Rails: The range includes the SingleRail 36 in various lengths and the SolidRail Light.
- Bricks beneath the hook: According to the K2 installation instructions, to prevent damage under high snow loads, the brick beneath the hook’s arm must be replaced with a metal roof panel or a sheet metal substitute tile (exception: SingleHook 2).
According to K2, the SingleRail is designed for roof pitches ranging from 5 to 75 degrees.
Metal roofing, trapezoidal sheet metal and sandwich panels
- Metal standing seam roof: Seam clamps are clamped onto the standing seam. According to K2, this can be done without penetrating the roof membrane.
- Trapezoidal sheet metal and sandwich panels: Here, a short rail is screwed directly onto the sheet metal; the MiniRail is available in the range. According to K2, the MiniFive attachment allows the modules to be raised by 5 degrees. For sandwich panels, approval from the panel manufacturer is required, according to K2.
Flat roof: raised, often without drilling
On flat roofs, the modules do not lie flat but are mounted at an angle on racks. According to the German Solar Industry Association, solar installations on flat roofs are overwhelmingly laid on top of the roof and ballasted, as this avoids penetrating the roof membrane.
The range includes the East-West Sets D-Dome 6.10 from K2 and individual components of the system. An overview of the Dome 6 variants:
| Dome 6, facing south | Dome 6, East-West (D-Dome) | |
|---|---|---|
| Mounting | according to K2, 10 or 15 degrees | according to K2 7, 10 or 15 degrees |
| Installation on roofs with a pitch of up to 3 degrees | Ballast, no penetration | Ballast, no penetration |
| roof pitch of between 3 and 10 degrees | Fixed connection (Dome FixPro) | Fixed connection (Dome FixPro) |
| Minimum distance from the edge of the roof | according to K2, usually 600 mm | according to K2, usually 600 mm |
Ready-made kits for east-west installations are available in the range for 2 to 12 modules.
South or east-west? According to the Consumer Advice Centre, you are free to choose between a south-facing and an east-west-facing orientation on a flat roof. Facing east or west, a single module generates less than when facing south, but the generation is spread more evenly throughout the day, from morning to evening.
Wall and balcony
For balcony power plants, there are brackets that hang from the balcony railing using hooks or are fixed to the wall, floor or metal roof with screws; these are available from Hantech. According to the instructions for the HNT-MH-41 universal bracket, the expansion plugs for concrete floors and balcony walls are not included, as they depend on the substrate.
The Consumer Advice Centre emphasises that the module must be secured in such a way that wind cannot damage or dislodge it, and that it cannot fall due to its own weight. Anyone living in rented accommodation or in a owners’ association should clarify the installation on a parapet or façade with their landlord or the association beforehand. Information on how much yield the balcony’s angle provides can be found under ‘Balcony power plant: yield and orientation’.
Structural analysis: check before assembly
A PV system adds extra weight to the roof; on a flat roof with ballast, this is significantly more than just the modules. According to the K2 installation instructions, it must be checked prior to installation whether the product meets the on-site structural requirements, and the load-bearing capacity of the roof must always be verified. K2 designs its systems in accordance with the Eurocode and, using the K2 Base software, provides a design including a parts list and structural analysis report.
A specialist contractor will determine whether your roof can support the system and how much ballast is required. Information on how much space the modules require and how modules, inverters and storage systems are combined can be found under ‘Planning a PV system’. All components are listed under ‘Substructure’. Details of which K2 components are suitable for which roof can be found under ‘K2 substructure: Which components are suitable for which roof?’.
