Photovoltaics have become an increasingly popular option for individuals and businesses seeking to reduce energy costs and minimise environmental impact. However, many potential investors wonder how the installation of photovoltaic panels may affect the strength of their roof. In this article, we take a closer look at the load on a roof with a photovoltaic installation and discuss what factors are worth considering

Photovoltaic panels – what is the roof load in kg?

Photovoltaics can be a heavy load on a roof, and not every roof structure can support this. For example, a single 415 Wp bifacial photovoltaic panel weighs around 25 kg. To install a 10 kWp system, we need as many as 24 such panels, which already gives a weight of PV modules of around 600 kg. To the total weight of the installation, we also need to add the weight of the supporting structures, ballasts, as well as intermediate elements such as cabling and installation accessories. As a result, the weight of the entire installation is several tens of kilograms per square metre. The roof structure may not be able to bear this load. Before installing the system, an expert assessment of the roof’s strength should be carried out in order to initially assess whether it is possible to install a photovoltaic system

Obciążenie dachu instalacją fotowoltaiczną pokrytego blachodachówką
Figure 1: Plan of a tiled building

Can I install panels on my roof? What could be the contraindications?

This is one of the first questions that arises for people interested in installing photovoltaic modules. If there are signs of corrosion on the trapezoidal sheet or tile roof, it is necessary to thoroughly remove the rust and apply a suitable anti-corrosive agent or replace the damaged components. The same applies to concrete and ceramic roof tiles – if they are cracked, it is necessary to replace them before installing photovoltaic panels. It is also important that the roof structure, especially the roof trusses, are in proper condition. The rafters must not be moulded or damaged, as installing photovoltaics on a weakened roof structure can even lead to a building disaster

It is also important to note that solar panels cannot be installed on roofing made of eternit. This is due to the presence of asbestos, which was used to manufacture this type of roofing

How does a photovoltaic installation positively affect the strength of the roof?

Photovoltaic modules not only act as an energy source, but are also an integral part of the protection of the roof structure. The panels protect our roof from

fotowoltaika obciążenie dachu na blasze trapezowej
Figure 2: Photovoltaic installation on trapezoidal sheet metal

Summary

Installing photovoltaic panels on a roof can affect the strength of the roof, but a properly planned and professionally carried out installation process can simultaneously improve the protection of the roof structure. It is important to consult experienced photovoltaic specialists who will carry out a thorough assessment and ensure that the installation is safe and effective. This way, you can enjoy the benefits of solar energy while ensuring the longevity of your building’s roof

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