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The advantage of a flat roof is that there is a lot of flexibility when it comes to the placement of the solar panels. Since solar panels oriented towards the South provide the greatest return, people often choose to install solar panels on flat roofs facing South. However, there may also be reasons to place the solar panels differently. For example, when solar panels are placed along the roof edge, more solar panels fit on the flat roof.
Do you have a flat roof, but only limited space available on it? In that case, it may be advantageous to place the solar panels in an East-West arrangement and make optimal use of the space in this way. This arrangement provides a lower return per panel, but the total yield will be higher because more panels can be installed. In this setup, the yield is also spread more evenly over the day. This offers advantages if you want to consume the electricity at the same time as it is produced. This becomes extra interesting in view of the phasing out of net metering at some point in the future.
Slope angle
In most cases, the solar panels are placed in rows behind each other on flat roofs. To prevent shadows from row upon row, the rows are always placed slightly apart. In this way the yield per panel is optimal. The minimum distance required between the rows depends on the angle of inclination. The angle of inclination is usually between 10 and 15 degrees. As a result, the panels lie relatively flat, which means that the wind has less influence on them, but they are still slanted in such a way that any dirt is automatically washed off by the rain. The smaller the angle of inclination, the closer the rows of solar panels can be to each other and the more solar panels fit on the flat roof.
Landscape or portrait
Solar panels can be placed in two ways: horizontal (landscape) or vertical (portrait). In almost all cases, solar panels on a flat roof are placed in landscape position. This has to do with the wind and the required ballast. If the solar panels were placed in portrait position on a flat roof, they would stick out a lot more above the roof edge. The result is that the solar panels catch more wind and there is a higher risk of the panels shifting. This requires much more ballast and the roof must be designed for this.
Distance to the roof edge
For flat roofs, also keep in mind that there must be sufficient distance between the solar panels and the roof edge. Wind forces can increase significantly at the roof edge, which could cause the solar panels to shift. That is why the roof edge is a so-called no-go zone for solar panels. Usually the no-go zone is 0.5 to 1 meter from the roof edge. If you move closer to the roof edge, more ballast will be needed.
Because the solar panels are mounted separately on the flat roof, it is necessary to place ballast in the substructure so that the panels do not shift an inch, even during heavy storms. Weight used as ballast depends on the mounting system. Concrete or tiles are often used. The ballast calculation depends on the height of the flat roof and the environment (open or built-up), where in the Netherlands the house is located (for example, more ballast is needed in coastal areas) and the distance between the panels and the roof edge.
"A good installer always ensures a correct ballast calculation that is tailored to your situation."
Once the configuration has been determined, we can begin laying the panels. There are many options for mounting systems on a flat roof. We often work with mounting materials from the Sunbeam brand. The big advantage is that this type of material requires less ballast, making it suitable for most roofs. The frames are made up of beams, feet and supports. These are aligned depending on the size of the solar panels. Resting on the frames there will be a ballast plate on which the ballast, such as pavement tiles, can be placed. The solar panels are then placed on the supports and secured with clamps. Depending on the mounting material, the open sides between the angle of inclination and the solar panels can be covered with wind plates.
So a lot is possible on a flat roof and in most cases solar panels are very profitable. Our advisors are happy to think along with you and can help you find the best solution for your flat roof.
South-facing roofs are most suitable for the installation of solar panels, because they allow maximum use of direct sunlight. East- or west-facing roofs are also suitable. Poor returns are achieved by North-facing roofs, because these roofs receive too little direct sunlight. That is why the advisors always try to find a solution to allow the solar panels to face south as much as possible.
read more ›Zonnefabriek can install solar panels on both flat and sloping roofs. If possible the Sunbeam mounting system is used for flat roofs. This system uses less ballast and helps to limit the weight pressing onto the roof. For sloping roofs, the Zonnefabriek uses the Schletter mounting system, a sturdy system that puts as little ballast as possible on your roof tiles.
read more ›Zonnefabriek has various mounting systems for flat and sloping roofs. If installation is not carried out correctly, it can damage the solar panel and the roof and the efficiency can suffer. It is therefore important to eliminate errors during the installation.
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