With the UK government’s commitment to reaching carbon net zero by 2050, planning legislation regarding solar panels has been relaxed to facilitate an increase in installations.

Solar panels can be installed in most cases under permitted development (PD) rights, which avoids the need for planning permission. However, rules still apply, and in some areas your PD rights may be restricted or removed altogether.

If you’re thinking about installing solar panels, our concise guide on planning rules and design considerations will help you plan your project.

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Types of Solar Panels

Before we get into planning specifics, it’s worth briefly describing what we refer to as "solar panels", as the term is often used generically to describe different technologies.

There are two main types:

1. Photovoltaic (PV) panels or tiles that use the sun’s energy to generate electricity.
2. Solar thermal panels or collectors, manufactured as flat plates or tubes, that use the sun’s radiation to heat water.

Both PV and solar thermal panels can be installed under permitted development.

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Surface mounted PV panels by AES Solar.

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Permitted Development Rights for Solar Panels

The Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 14 sets out guidance for the installation of solar panels on residential properties – flats and houses – which removes the need for planning permission.

Note that Article 2(3) land, also referred to as ‘designated land’, includes conservation areas, Areas of Outstanding Natural Beauty (AONB), and World Heritage Sites.

Class A - Roof and wall-mounted panels

• Must be located on the building or within the curtilage of the site.
• Must not protrude more than 0.2 metres beyond the roof slope or wall.
• On flat roofs, panels can protrude up to 0.6 metres.
• Should not be higher than the highest part of the roof (excluding chimneys).
• Should be removed when no longer needed.

Article 2(3) land

• In conservation areas and World Heritage Sites, panels cannot be installed on a wall facing a highway. They can, however, face the highway if installed on a pitched roof.

Class B - Ground-mounted solar panels

• Only one ground-mounted system is allowed per property.
• The maximum height of the system must not exceed 4 metres.
• The total area of the panels must not exceed 9 square metres.
• The installation must not extend more than 3 metres in any direction.
• Panels must be at least 5 metres away from the property boundary.
• The installation cannot be closer to a highway than the nearest part of the house.

Article 2(3) land

• The maximum height reduces to 2 metres if the installation is closer to a highway than the nearest part of the house.

For all installations, the panels should be sited to minimise their effect on the appearance of the building and the amenity of the area.

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Aerial view of a renovated terrace house by Bradley Van Der Straeten Architects featuring solar thermal panels on a dormer flat roof at the rear and PV panels on the front roof slope. Photo by French + Tye.

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Permitted Development Restrictions

Before installing solar panels on a flat roof located on Article 2(3) land, you must apply to your local planning authority (LPA) for prior approval to assess their impact on the appearance of the site. If the LPA deems the impact detrimental, then planning permission is required.

Buildings on Article 2(3) land may also be subject to an Article 4 direction, which limits certain permitted development rights. If your LPA has an Article 4 direction in place restricting the installation of solar panels, you’ll need to apply for planning permission. To see if this applies to you, check your local authority’s planning website.

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When Planning Permission is Required

Planning permission for solar panel installations is required:

• For listed buildings or scheduled monuments.
• If prior approval is needed.
• If there’s an Article 4 direction on the land.

Note that the above guidance relates to England. While PD rights are broadly similar across the UK, guidance can vary.

In Scotland, for example, planning permission is required for:

• Solar panels installed on flat roofs (the 1-metre height rule makes installations largely unfeasible).
• Walls of flats.
• The front of a property in a conservation area or World Heritage Site that is visible from the road.

Be sure to check your country’s legislation before processing too far with your installation.

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Ground-mounted solar PV panels by AES Solar.

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Seek Approval

As noted previously, if you live on Article 2(3) land, you must apply to your LPA for prior approval before installing solar panels on a flat roof.

For all other installations, you can gain peace of mind by applying for a Lawful Development Certificate from your LPA to confirm that you don't need planning permission.

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Design Considerations for Solar Panels

Solar panels aren’t the most attractive feature for homes. To preserve your home's appearance, consider their positioning and design.

If possible, place panels on the rear roof, away from the main frontage. Position ground-mounted panels in a discreet area can also help, though additional costs will arise for cabling.

In-line panels, flush with roof tiles, are more visually appealing than surface-mounted ones. Dark-coloured panels on slate roofs blend better with the overall look.

PV tiles offer a more discreet option for generating electricity, with some mimicking natural slates, though these tend to be more costly. A good option for properties in designated areas.

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In-line solar thermal panels by AES Solar.

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Other Consents

If your system generates over 3.68kW, the installer must notify the Distribution Network Operator (DNO) before installation.

All installations require building regulations approval. This involves ensuring that the roof can support the extra load, as well as electrical and plumbing certification.

Choose an MCS-certified contractor to install your solar panels. They will ensure that all approvals are met before the installation begins, which is also a requirement if you are eligible for a government grant.

If your solar panel installation is part of a wider series of home improvement works, an architect will be able to coordinate all of the building regulations-related work, including information provided by the MCS installer, and apply for approval.

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Checklist

• Solar panels can generally be installed under permitted development (PD) rights.
• There are specific regulations for conservation areas and World Heritage Sites.
• Installations on flat roofs in Article 2(3) areas require prior approval.
• Planning permission is needed for listed buildings, scheduled monuments, and areas with Article 4 directions.
• To ensure compliance, consider applying for a Lawful Development Certificate.
• Position panels away from principal frontages whenever possible and choose more discreet solutions like in-line panels or solar tiles to enhance the visual appeal.
• For standalone installations, use an MCS-certified installer to handle both technical and regulatory requirements.

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The information provided in this article is intended for general guidance and educational purposes only. For specific expert advice on your project, consult a skilled residential architect featured on Designs in Detail.

About the Author

Aron Coates is an architect with over two decades of experience, working on projects ranging from historic building restoration to contemporary home design.

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