Ground mounted solar arrays in a domestic garden

A ground-mounted array in your back garden can be permitted development, but the limits are tight enough that many of the arrays people actually want need a planning application. The ground mounted solar garden permitted development right sits in Class B of Part 14 of the Town and Country Planning (General Permitted Development) (England) Order 2015, and it allows one stand-alone installation per curtilage, up to 4 metres high, with a surface area of no more than 9 square metres and no dimension over 3 metres, kept at least 5 metres back from the curtilage boundary.

Nine square metres is roughly four or five panels. If your quote is for a 6 kilowatt array on a frame at the bottom of the garden, you are outside the right and into a householder application.

What the stand-alone domestic class permits

Part 14 splits domestic solar in two. Class A deals with equipment on the dwellinghouse itself or on a building within its curtilage. Class B deals with stand-alone solar for domestic premises, which means panels on their own frame or post rather than fixed to a building.

Class B covers both solar photovoltaic equipment and solar thermal collectors, along with alterations to an existing stand-alone installation. It applies to a dwellinghouse and to a block of flats, which catches communal arrays in the grounds of a converted house as well as single homes.

The right exists for microgeneration, a term the Order borrows from section 82 of the Energy Act 2004. That definition sets a ceiling of 50 kilowatts of electrical capacity or 45 kilowatts thermal. Domestic gardens run out of space long before they run out of capacity, so the capacity ceiling rarely bites.

Height, area and boundary limits

Four numbers decide most cases.

The 9 square metre figure is the surface area of the solar equipment, not the footprint of the frame or the fenced compound around it. The 3 metre dimension limit includes any housing, so an inverter cabinet bolted to the frame counts towards the measurement. Height is taken to the highest point of the equipment in its installed position, which on a tilted frame is the top edge of the rear panel row.

The 5 metre boundary standoff is the limit that most often kills a scheme. A typical suburban garden is 8 to 10 metres wide, which leaves a strip in the middle and nothing like the clear southern aspect the installer wanted. Measure it from the curtilage boundary, which is not always the fence line if part of the garden was bought from a neighbour, and say so on the block plan.

The one installation per dwelling restriction

Class B permits only the first stand-alone solar installation within the curtilage. A second array needs planning permission, however small it is and however far it sits from the first.

This catches two situations regularly. One is the household that puts in a modest array, likes the result, and wants to double it two summers later. The other is a property with an existing stand-alone solar thermal collector for hot water, where the owner has forgotten it counts.

Adding panels to an existing frame is the better route when it works, because alteration of an existing stand-alone installation is within Class B as long as the resulting installation still meets every limit. Nine square metres remains nine square metres.

Visibility from the highway and designated land

In a conservation area or a World Heritage Site, the right is lost if any part of the installation would be nearer to a highway bounding the curtilage than the nearest part of the dwellinghouse is to that highway. In plain terms, a front-garden array in a conservation area is out.

Note that the test is about the highway boundary, not about whether the array can be seen. A side garden fronting a lane is a highway frontage even if a hedge screens it today, because hedges get cut down.

A condition also applies everywhere: the equipment must be sited, so far as practicable, to minimise its effect on the external appearance of the building and the amenity of the area. That is a genuine obligation rather than decoration, and it is the hook an enforcement officer uses when an array has been parked against a shared boundary in full view of three neighbours. The same reasoning that decides what counts as incidental to the enjoyment of a dwellinghouse applies to siting judgements of this kind: the question is the real effect on the ground.

An Article 4 direction can remove the right altogether. Councils have used Article 4 over householder rights in some conservation areas, so check the designation before ordering a frame.

Listed buildings and their curtilage

Class B does not apply at all if any part of the equipment would be within the curtilage of a listed building or a scheduled monument. Not reduced, not conditional. Removed.

Curtilage is wider than most owners assume. The garden of a Grade II listed farmhouse is normally within its curtilage, and so is the paddock immediately behind if it has been in the same enjoyment since listing. An array there needs a householder planning application, and if a wall, outbuilding or hardstanding has to be altered to take it, listed building consent may be needed too.

The practical consequence is a longer document set. A Planning Statement explaining the microgeneration purpose, a heritage assessment proportionate to the significance affected, and elevations showing the array against the historic building are the usual minimum. The council's validation list will say what else it wants.

Removal when no longer needed for microgeneration

The second Class B condition requires the equipment to be removed as soon as reasonably practicable when it is no longer needed for microgeneration.

Dead panels left on a frame for a decade are a breach of condition, and the obligation sits with whoever owns the land at the time rather than with the installer. It also means the frame itself has to go, not just the glass.

Keep the commissioning paperwork, the generation meter readings and the inverter warranty in the property file. If an officer or a buyer's solicitor asks whether the installation was lawful, the evidence that it was installed for microgeneration and is still generating is what answers the question. Where the answer needs to be formal, a Lawful Development Certificate under section 192 of the Town and Country Planning Act 1990 is the only route that carries weight.

Comparing a ground array with a roof installation

Roof-mounted equipment under Class A is the more generous right for most houses. There is no 9 square metre cap, which is why a full roof of panels is normally permitted development while four panels on a frame may not be.

Class A has its own limits instead. Equipment must not protrude more than 200 millimetres beyond the roof plane or wall surface, and must not sit above the highest part of the roof, excluding the chimney. On a flat roof the ceiling is 1 metre above the roof surface. On designated land, panels must not go on a wall fronting a highway.

So the ground array earns its place where the roof cannot take panels: a north-facing or heavily shaded roof, a thatched or slated roof the structural engineer will not load, or a flat roof already full of plant. Shade matters more than orientation in most gardens, and a tree you cannot fell because it carries a Tree Preservation Order will beat any amount of clever mounting. The same practical thinking applies to the drainage condition attached to hard surfaces under Class F when you lay a maintenance path to the array.

Where the array exceeds a Class B limit, treat the application as a straightforward householder one and front-load the case: generation figures from the installer, a shading study, a site section showing the array against the boundary fence, and a short note on glint and glare if a road or railway faces the panels. For the full picture of how the roof-mounted right compares, read the detail on solar panels on a house under Part 14 Class A, and if you want a view on which supporting documents your site is likely to need, enter your postcode on PlanScope.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it, and remember that a Lawful Development Certificate is the only formal way to confirm that works are lawful. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.