Everything you need to know about solar panels on a flat roof

By Jessica Sletmo

Solar energy is an excellent way to reduce your energy bills and environmental impact. There are several factors that can influence how much energy your PV system will generate, one of which is the slope of the roof.

In the UK, roof shapes and types vary but flat roofs have become common in new developments in recent years. In this article, we cover everything you need to know about installing solar panels on a flat roof.

What is the best angle for solar panels?

The short answer is that to get the most out of your green investment, the PV panels should be mounted on the roof at an angle that best optimises sunlight exposure for that location. 

Flat-roof solar panels can be placed in specially designed frames to create a desired angle toward the sun.

Can you put solar panels on a flat roof?

It‘s very possible to install solar panels on a flat roof, and MakeMyHouseGreen installers are qualified to do so. 

For a flat roof solar installation, installers will use the same type of solar panel as on pitched roofs, however, extra considerations will need to be made to ensure your PV system can produce the maximum amount of energy from the sun. 

Rest assured, our expert Green Home Gurus will be able to determine the best setup for your property. The option to book a free consultation call will be presented to you when using our impartial tool.

How do solar PV systems on a flat roof work?

Solar panels on a flat roof will work the same way as solar panels do on other roofs! The only difference is that to capture as much sunlight as possible, flat roof solar panels need to be artificially raised to a 20–50-degree angle. Installers will create the angle by using specially designed tilted frames for solar panels.

Also bear in mind that you might not be able to fit as many panels on a flat roof as you would on a pitched roof. To avoid shading from the raised structure of the panels, there needs to be about a metre gap between each row of solar panels on a flat roof. This makes the shadow from the panels fall on an area where there aren’t any panels. A pitched roof can have the panels placed closer together which is why you’d be likely to fit more panels.

The risks associated with PV systems on flat roofs can be resolved by installing the appropriate structures. For example, potential damage by high winds can be prevented by either fixturing or weighting down the solar panels. 

Check out this helpful article for other things to keep in mind when working out whether solar panels are right for you.

What are the benefits of having solar panels on a flat roof?

Some of the advantages of installing solar panels on flat roofs include:

Flexible system design: When mounting solar panels to a sloping roof, installers will need to work with the existing angle and pitch of the roof. For flat roof panel installations, the solar panels will be placed on frames that can be angled as desired. This way, your system can capture as much of the sunlight as possible. 

Possibly cheaper and quicker installation process: As mentioned above, the same solar panels are used on flat roofs as on pitched roofs, however, for flat roofs, installation costs may be reduced as a flat location is sometimes more accessible and safer than a slanted one, which would eliminate the need for scaffolding. Bear in mind that an additional cost to a flat roof solar panel system is the cost associated with the solar frames used to tilt the panels.

Self-cleaning: Correct maintenance will keep your solar panels working efficiently and help minimise wear and tear. As you already know, specially designed brackets will keep the panels on flat roofs tilted. When it rains in the UK, water will help the panels ‘self-clean’ and prevent damage from pooling water.

Safer maintenance: Solar panel maintenance and repairs are easier on flat roofs as there is often more space around the panels for someone to stand when working on the panels.

Better looking configurations: Panels on flat roofs are less likely to be visible from the street.

Can you put solar panels on the garage roof?

Absolutely! The garage can be an excellent choice for solar panels if it receives more sunlight than the house. For a successful installation, it will be essential to ensure that:

  • there is enough space for a PV system that covers your energy needs,
  • the garage has a cable route running to the main consumer unit in the property,
  • the roof is structurally sound, 
  • and the roof is in a good shape.

You will need to allow enough space when calculating how many solar panels fit on your garage roof. Remember that any row of solar panels needs to be around one metre away from the solar panels in front of them, from the sun’s perspective. This is to avoid shading from the raised profile of the panels. Our expert Green Home Gurus will happily help with the maths.

Can I put solar panels on my shed roof?

As with garage roofs, in the UK, solar panels can be mounted on shed roofs provided that your roof can support the weight of solar panels. Typically, installing solar panels on shed roofs is not advised and there are three reasons for this:

  1. If you want to install some solar panels on your main property and some on your shed, you may need another string on the inverter, which would increase the installation cost.
  2. The roof is not typically structurally sound enough for solar panels. However, it is possible and a structural survey can be arranged to ensure that the roof is in good shape and that a solar panel system installation would be up to standard.
  3. It might be less economical in the long term compared to solar panels mounted on the main roof.

The exact calculations will depend on your energy needs and shed‘s purpose. By using the MakeMyHouseGreen tool it takes only a few minutes to find out how much energy your solar panels could generate.

Do you need planning permission to put solar panels on a flat roof?

Planning permission is necessary if solar panels would increase the height of the property by more than 20cm when installed on the roof. Normally this is only the case if the flat roof is at the very top of the structure.

If in doubt, check with The Planning Portal – the national planning application service for England and Wales – or get in touch with one of our expert Green Homes Gurus who will help with the solar system design and walk you through the requirements. 

In summary, with a correctly designed system, solar panels on flat roofs can be as effective as on pitched roofs!

We’re here to provide you with all the other tools needed to work out which green home improvements would work best for you – simply check out our Green Guides section or drop us an email via team@makemyhousegreen.com.

Recommended Guides:

- How many solar panels will fit on my roof?

- Do solar panels work without sunlight?

- How do solar panels work?

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