The question of whether installing solar panels on a flat roof is beneficial arises.

Installing solar panels on flat roofs can be a viable option for homeowners and property developers. Here's what you need to know about the process, benefits, and considerations.

Solar panels on flat roofs are identical to those used on pitched roofs, but the installation process requires different methods. Monocrystalline solar panels, known for their high efficiency and durability, are often the best choice for flat roof installations.

One of the advantages of installing solar panels on flat roofs is ease of access. Compared to pitched roofs, flat roof installations are usually easier, safer, and quicker due to the absence of steeply sloping roofs. However, it's important to note that the cost is generally around 20% more due to additional materials and installation costs for the mounting system and structural engineer fees.

The weight of a typical solar panel system can range from 10 to 25 kg per square metre, which may require structural strengthening work on existing flat roof structures. A good mounting system is critical for solar panels on a flat roof, as it allows the panels to be tilted toward the sun and maximizes their efficiency.

The most commonly used mounting systems for solar panels on flat roofs are ballasted systems. These systems fix the panels by their own weight plus additional ballast (e.g., concrete blocks) without penetrating the roof membrane, preserving roof integrity and ensuring water tightness. These systems typically tilt the panels between 6° and 13° or use east-west orientations to optimize sunlight capture.

Adjustable racking systems are also commonly used to achieve the best angle for the specific location. Tilted panels allow rainwater to drain and wash away dirt and debris, keeping them clean and in good working order.

Regular cleaning is necessary for solar panels on flat roofs to remove the build-up of dirt, which impairs their efficiency. It's crucial to ensure any penetrations through the roof covering during installation are done correctly to prevent leaks and maintain the roof covering warranty.

Most installations on flat roofs won't need solar panel planning permission thanks to recent changes to permitted development rules. However, if the solar panels are visible from the street, located on designated land, or if the property is a listed building, planning permission will be needed for the installation.

Flat roofs of buildings like garages and extensions can provide valuable locations to install renewable technologies such as solar panels. With proper planning and the right mounting system, solar panels on flat roofs can be a practical and effective way to harness solar energy.