UK Standalone Solar Permitted Development: GPDO Class B Guide

Key Takeaways

• A standalone solar array must not exceed 4 metres in height (August 2026).
• The solar panel surface area is limited to 9 square metres (August 2026).
• The array's maximum dimension, including housing, is 3 metres (August 2026).
• Installation within 5 metres of a boundary requires full planning permission (August 2026).

What is GPDO Class B for standalone solar?

The Town and Country Planning (General Permitted Development) (England) Order 2015 (S.I. 2015 No. 596) Schedule 2 Part 14 Class B defines permitted development rights for standalone (ground-mounted) solar arrays. This class applies to the "installation, alteration or replacement of stand-alone solar for microgeneration within the curtilage of a dwellinghouse or a block of flats." This means you can install a ground-mounted solar system without needing a full planning application, provided it meets specific criteria.

We verified these provisions by directly consulting the official UK legislation, specifically The Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2 Part 14, as accessed on 23 August 2026.

What are the size limits for standalone solar under Class B?

GPDO Class B sets clear limits on the physical dimensions of standalone solar installations to qualify as permitted development.

| Maximum Array Dimension Limit | "or any dimension of its array (including any housing) would exceed 3 metres." | Figures as of August 2026.

These limits mean that if your proposed standalone solar array exceeds 4 metres in height, has a total panel surface area greater than 9 square metres, or any single dimension of the array (including its housing) is larger than 3 metres, it will require full planning permission.

Are there restrictions on location for Class B standalone solar?

Yes, GPDO Class B includes several location-specific restrictions. These aim to protect amenity, heritage, and public safety.

| Scheduled Monument Exclusion | "would be installed on a site designated as a scheduled monument; or" | Figures as of August 2026.

Specifically, you cannot install a standalone solar array within 5 metres of your property's boundary under Class B. If you do, it automatically requires full planning permission. Furthermore, installations within the curtilage of a listed building or on a scheduled monument are prohibited. In a World Heritage Site, the array must not be closer to a highway than the nearest part of your dwelling; in a conservation area, this is instead allowed under a 2 metre height limit with prior approval.

How many standalone solar arrays can I install under Class B?

GPDO Class B limits the number of standalone solar installations you can have within your domestic curtilage. The legislation states that "the development would result in the presence within the curtilage of more than 1 stand-alone solar." This means you are permitted to have only one standalone solar installation as permitted development under Class B (August 2026). If you wish to install a second standalone array, you will need to apply for full planning permission.

What are my responsibilities regarding amenity and removal?

Even if your standalone solar installation meets all the dimensional and locational criteria for permitted development, you still have responsibilities regarding its impact and future. The legislation mandates that "stand-alone solar is, so far as practicable, sited so as to minimise its effect on the amenity of the area." This means you should consider how the array looks from public spaces and neighbouring properties.

Additionally, "stand-alone solar is removed as soon as reasonably practicable when no longer needed." This ensures that disused installations do not become eyesores or hazards.

Navigating Permitted Development for Ground-Mounted Solar

Understanding GPDO Class B is crucial for planning your ground-mounted solar project. The rules are specific and any deviation means you must seek full planning permission. For example, if your array is within 5 metres of your boundary, or if you already have one standalone array and plan another, you will need to apply for planning permission. We have not verified specific local authority interpretations, so always check with your local planning department.

For roof-mounted solar, different rules apply. You can review the UK domestic solar permitted development GPDO Class A guide for details on those regulations. If you are considering commercial solar projects, the UK commercial solar permitted development GPDO Class J guide or the UK carpark solar canopy permitted development Class OA guide may be relevant.

To determine the appropriate size for your system based on your energy needs, you can use a solar sizing tool. This can help you understand if your desired system falls within the 9 square metres surface area limit for panels under Class B.