A Guide to Solar Panels on Flat Roofs

As solar energy continues to boom in Ireland and across the world, many of us may have begun to consider how suitable our own homes are for solar.

You may have heard that domestic solar panels are commonly installed on sloped roofs directly facing the suns rays. While this may have once been optimal for renewable electricity generation, nowadays, it is certainly not a requirement.

In recent years, flat roofs have become more commonplace across our new buildings. If you live in a flat roofed home and you're wondering how well it is suited to solar energy generation, then we're here to tell you that yes, you can still install solar panels and enjoy their benefits to the fullest.

Top Tips for Installing Solar Panels on Flat Roofs

Remember, if your roof doesn't face south, installing solar panels is still possible, although their efficiency may be affected.

For steep rooftops, a "penetration mount" involves drilling holes to secure the racking supporting solar panels. However, flat roof solar panel mounting systems differ. Commonly, weighted mounting systems or "ballast systems" are employed, eliminating the need for holes.

In these systems, gravity secures the installation above your roof, simplifying the installer's job. Another option is the Bauder roof system, known as BauderSOLAR, ideal for flat roofs. This system integrates the solar PV module and substructure into a single unit fastened to the roof without penetrating its waterproofing.

This ensures the roof's integrity during installation. Additionally, it's exceptionally lightweight, ranging from 9 to 12.5 kilograms per square meter, depending on the module selected.

What roof pitch is best for solar panel installation?

When considering solar panel installation, it's important to assess the optimal roof pitch for your specific needs, taking into account the advantages and disadvantages associated with each pitch type.

Flat Roofs

Flat roofs are prevalent in Ireland, making them a common consideration for solar panel installation. The benefits of installing solar panels on flat roofs outweigh the drawbacks.

Advantages include cost-effectiveness due to the use of less material per square foot, a straightforward and quick installation process, reduced visibility from the street, and simplified maintenance.

However, you could run into some potential issues, such as standing water, which can pose a threat to fixtures, particularly with inadequate drainage.

Low-Sloped Roofs

Low-sloped roofs are another viable option for solar panel installation in Ireland. These roofs offer advantages such as requiring fewer roofing materials per square foot, facilitating easier and safer installation and repair processes, and they have better drainage.

Nevertheless, it's important to note that low-sloped roofs may experience a longer melting process during heavy snowfall, potentially putting more pressure on fixtures. Adherence to local building codes is crucial for safe and compliant installations.

Pitched Roofs

Although pitched roofs may be less common, they still play a role in Ireland's architectural landscape.

The advantages of installing solar panels on pitched roofs include better run-off for debris, water, and snow, reducing the likelihood of water buildup that could lead to leaks and mold damage.

However, the sloped nature of these roofs introduces challenges in the installation, maintenance, and repair processes, potentially making them less safe and more expensive. Therefore, careful consideration and professional expertise are essential when opting for solar panels on pitched roofs.

Which Roof Material Works Best with Solar Panels?

When considering solar panel installation and how many solar panels you need, it's essential to evaluate the compatibility of your roof material.

Different materials can accommodate solar panels, but each comes with varying impacts on installation costs. While wood roofs are generally not recommended due to the heightened risk of electrical fires, other common materials offer feasible options.

Asphalt Shingles

As one of the most prevalent roofing materials in Ireland, asphalt shingles provide a robust and composite foundation for solar panel installation. The process involves securely fastening solar panels by drilling through the shingles into the roof foundations. Metal flashing around the drill holes prevents leaks, ensuring a reliable and leak-proof integration.

Metal Roofs

Metal roofs prove highly compatible with solar panels, enabling swift and uncomplicated installation. The durability of this recycled material allows brackets to directly clamp onto seams, eliminating the need for drilling and ensuring a leak-proof setup. Standing seams on flat metal panels further enhance solar exposure by enabling panel tilting.


Clay or concrete tiles, commonly found across Ireland's roofs, offer longevity and leak resistance. However, installing solar panels on tile roofs may incur higher costs due to the complexity and risk involved. The brittle nature of these tiles, especially those made from clay, necessitates careful installation. Installers typically remove tiles, secure brackets to roof rafters, reposition the tiles, and connect rails to the brackets.

Tar and Gravel

Frequently used in flat roofs, tar, and gravel compositions provide a stable foundation for solar panels. Alternatively, panels can be affixed to cinder blocks on the flat surface. However, achieving the optimal 30-40 degree angle for sunlight exposure may require additional brackets, contributing to overall installation costs. Despite this, flat roofs remain suitable for solar panel integration.

Do I Need Planning Permission for Flat Roof Solar Panels?

For flat roofs, obtaining planning permission is a requirement when installing solar panels. This is because solar panels on flat roofs are typically placed in frames to angle towards the sun. This arrangement often involves a protrusion exceeding 0.2 meters above the roof slope, contradicting the rules of "permitted development."

When it comes to listed buildings, solar panels can be added, but obtaining permission is crucial. Any alteration that may impact the building's characteristics as a historically significant site necessitates approval.

In conservation areas, specific restrictions apply. While solar PV installation is allowed, it must remain invisible from public roadways. For more information on solar panel planning permission details, you can refer to the Planning Portal website.