Do You Need a Pitched or Flat Roof for Solar Panels?

Solar Panels have become increasingly popular as renewable energy solutions for homes and businesses alike. They offer a sustainable way to generate electricity and reduce reliance on traditional energy sources. But what if you have a flat-roofed property? Can you still take advantage of solar power?

The answer is yes, you can have solar panels on a flat roof. However, there are some considerations and additional equipment needed to ensure their effectiveness and longevity.

How do solar panels work on a flat roof?

The solar panels used on flat roofs are the same as those used on pitched roofs. However, when installed flat, they might not absorb as much sunlight, and there’s a risk of water damage. To avoid these issues, a framing system is essential to tilt the panels towards the sun. This not only maximises their sun exposure but also facilitates self-cleaning during rain showers, preventing water pooling and potential damage. 

There are two main options for framing systems on flat roofs:

Fixing panels to your home - This involves drilling into the roof and securing brackets to stabilise the mounting frame. Care must be taken to maintain the roof’s watertight integrity during installation. 

Adding weight - If penetrating the roof is not an option, an alternative is to add weight to the structure. The mounting frame can be placed into concrete ballasts (heavy slabs) or specialised tubs weighted down with slabs. 

Advantages and Disadvantages of flat roof solar panels

Like any solar panel installation, there are advantages and disadvantages to consider when installing them on a flat roof. 

Advantages

• Easy access to installation and maintenance: Flat roofs allow easy access for installers to perform maintenance without the safety risks associated with sloped roofs. 
• Aesthetics: Solar panels on flat roofs are less visible from the street, preserving the property’s appearance.
• Electricity bill savings: Solar panels can significantly reduce electricity bills, leading to substantial savings annually. 
• Reduced carbon footprint: Solar panels contribute to a greener environment by reducing carbon emissions 

Disadvantages

• Dirt accumulation: Without the tilted angle, dirt and debris can accumulate on the panels, reducing their efficiency. 
• Reduced sun exposure: Flat-mounted panels may not receive as much sunlight as those on tilted roofs, potentially impacting energy generation. 
• Potential warranty concerns: Water sitting between the frame and glass coating may cause faster panel degradation, potentially affecting warranties. 
• Increased wind effects: Proper mounting systems are necessary to secure panels in windy conditions, adding to installation costs.

Optimum angle for flat roof solar panels

To maximise energy generation and avoid water damage, flat roof solar panels should be mounted at a 20-50 degree angle. This position allows panels to absorb more sunlight and facilitates self-cleaning during rain showers. Installers typically use specialised equipment to achieve the optimal angle and ensure proper panel security.

Planning permission for flat roof solar panels

In some cases, planning permission may be required to install solar panels on roofs, especially if the property is in a conservation area or is a listed building. It’s essential to check with the local planning authority before proceeding with the installation. 

Things to consider before installing flat roof solar panels

Several factors should be considered before installing solar panels on a flat roof:

Weather conditions - High winds in windy areas may require additional precautions, such as fixing panels to the roof or adding weight to them.

Cost - Flat roof solar panel installations generally cost about 20% more than pitched roof installations due to the need for extra materials and structural engineering. 

Potential savings - Solar panels can lead to significant long-term savings on electricity bills and reduce the property’s carbon footprint. 

Conclusion

Flat roofs can indeed support solar panels, making them a viable option for harnessing clean energy even in such settings. With the right framing system and mounting angle, flat roof solar panels can effectively generate electricity, saving money on energy bills and contributing to a greener environment. 

If you're considering installing solar panels on your flat roof, ensure you engage qualified professionals, comply with any necessary planning permissions, and explore various mounting options to optimise the system’s efficiency and longevity. Solar energy offers a promising path towards a more sustainable future, and a flat roof shouldn’t stand in the way of embracing this green revolution.