Homeowner Blog

Planning Permission for Flat Roof Solar Panels.

Charlie McGibbon · 22 Dec 2023

Recently, the Government announced a series of measures aimed at cutting red tape around the installation of solar panels. One of these was removing the planning regulation requirement around installing solar panels on domestic flat roofs, bringing this in line with commercial properties. But if you have a domestic flat roof and are looking to take advantage of this new state of affairs, what other considerations should you bear in mind?

How much space do you need to install solar on a flat roof?

This is the biggest consideration for solar panels on a flat roof. You will need to be able to install at least six panels to make the system economically viable, at Spirit we wouldn't recommend installing a system smaller than this as it will be a lot harder to recoup the investment in saved electricity cost. This is because upfront costs such as scaffolding remain even if you install 1 or 10 panels!

As a rough guide, six standard panels will take up 16 to 20 m² given the standard size of a panel being 1.8 m x 1.1 m. Ideally there should be at least 0.6 m - 1.5 m for adequate spacing between the roof edges and the solar panels to allow for safe edge protection. If the space on your roof is less that this, it may not be economically viable to install solar panels.

Is your roof strong enough to support solar panels?

Installing solar panels on flat roofs means extra racking and ballast is required so that the solar panels can be fitted at the most efficient pitch facing the Sun. While pitched roofs are usually strong enough to support the weight of a solar panel system, it is more common for flat roofs to fall short due to the extra ballast required.

At Spirit Energy we will always advise a structural survey as part of the planning process to ensure that your flat roof can support the extra weight. If you have roof plans showing the beam sizes of the flat roof these can be used for a structural sign off, otherwise an intrusive survey may need to be done to assess the size of the beams and strength of the roof if you are unsure the roof can take the additional weight. Non-penetrative ballasted systems do help keep costs down otherwise a roofer needs to be brought in to weather fixings between the panel mounting system and the roof.

Is access easy and how much shading is there?

Easy access to the roof is more important when installing on flat roofs, as the ballast which can be heavy tiles or lintels need to be lifted up with your solar panels. This means small tricky flat roofs with difficult access can be expensive to install upon once suitable safe access has been included within our quote. Guardrails that sit on the flat roof will reduce the usable space, where even railing supported from the ground will require some space at the edge of the roof. It is also worth considering shading, as it is often the case that shading from nearby buildings can be much more of an issue on flat roofs.

See our Knowledge Bank article for more information

For more detailed information on the ins and out of flat roof solar panels, including the all important factor of what angle to use, please see out knowledge bank article here.

For more information on if your flat roof is suitable for a solar panel array, get in contact with us on 0118 951 4490 or email info@spiritenergy.co.uk today. Our expert technical sales team will be more that happy to provide you with no cost, no obligation advice and explore your plans for solar and ensure they don't fall flat.



Topics: Solar PV