Do You Need Planning Permission for Solar Panels on a Barn?

The short answer: usually no planning application — but over 50 kW you need prior approval

For most working barns, putting solar panels on the roof does not need a planning application. Rooftop solar PV on an agricultural building is normally permitted development — a category of works the government has already granted consent for, so you do not have to apply to your local planning authority for planning permission before you start.

There is one step the larger systems cannot skip. Up to 50 kW counts as microgeneration and is straightforward permitted development. An array over 50 kW — larger commercial arrays such as a 300 kW poultry roof — needs a prior-approval application to the council first. That is not a planning application: the council can only look at the design and external appearance of the array, in particular glare on neighbouring occupiers. It may tell you approval is not required, and if it has not answered within 56 days you can go ahead.

There are real exceptions, and getting them wrong can mean an enforcement notice and panels you are ordered to remove. So while the headline is reassuring, it pays to confirm exactly which side of the line your barn sits on before anyone climbs a ladder. This guide explains the permitted-development rules for barn solar, the situations where you do need consent, and the practical steps to confirm your own barn’s status.

How permitted development works for barns

The rules live in the Town and Country Planning (General Permitted Development) (England) Order 2015 — the GPDO. Solar on a building that is not a house or a block of flats — a barn, a shed, a grain store — sits under Class J of Part 14. Houses and flats use Class A of the same Part, which is why advice written for homeowners does not map neatly onto a working barn. Class J covers microgeneration solar PV and solar thermal on a building and, for larger systems, other solar PV on the roof of a building.

For a rooftop array on an agricultural building, the main conditions you need to meet are:

• On a pitched roof, the panels must not protrude more than 0.2 m beyond the plane of the roof slope. In practice this rules out steeply tilted A-frame mounting on a low-pitch barn roof, but it is no obstacle to in-plane mounting that follows the roof line — which is exactly how panels are fitted to a profiled-steel or fibre-cement barn roof anyway.
• On a flat roof, the highest part of the array must be no more than 1 m above the highest part of the roof.
• On any roof, the panels must not be installed within 1 m of the external edge of the roof.
• The building must not be listed or in the curtilage of a listed building, and the site must not be a scheduled monument.
• The panels must, so far as practicable, be sited to minimise their effect on the external appearance of the building and on the amenity of the area, and the equipment must be removed when it is no longer needed.
• An array over 50 kW needs a prior-approval application before you start, as described above.

There is no overall capacity cap: the old 1 MW limit was removed in December 2023.

Crucially, permitted development covers the panels and their mounting — but it does not sweep up everything else. A new electricity connection above a certain size still needs a G99 application to your Distribution Network Operator, and if your scheme involves structural alterations beyond simply fixing panels to an existing sound roof, those works may have their own consents. Most barn arrays clear the PD bar comfortably; the value of a specialist is knowing where the edges are.

For the official position on what counts as permitted development, the Planning Portal solar guidance is the authoritative starting point.

When you DO need planning permission

Permitted development does not apply in a few specific circumstances. If any of the following apply to your barn, assume you need consent until you have confirmed otherwise:

• Listed barns. If the building is listed — Grade I, Grade II* or Grade II — permitted development for solar does not apply: you will need Listed Building Consent, and usually full planning permission alongside it. A barn within the curtilage of a listed building also falls outside permitted development, so it needs planning permission, and Listed Building Consent too if the council treats the barn as part of the listing. This does not make solar impossible; heritage barns are routinely fitted with discreet arrays, as we explain on our traditional and listed barns page and in our guide to putting solar panels on a listed barn. It simply changes the route.
• Article 4 directions. A local authority can issue an Article 4 direction that withdraws permitted-development rights for a defined area or type of building. They are not common, but they exist, and they can override the general PD position. A direction only removes the rights it names, so read what it actually covers.
• Ground-mounted arrays. Class J is about arrays on buildings. A free-standing ground-mount is a different matter and normally needs planning permission.

Conservation areas, National Parks, National Landscapes (AONBs) and the Broads do not take a roof array out of permitted development. On an unlisted barn, panels on the roof stay permitted development inside all of them. The only extra limit on this kind of land is for panels fixed to a wall that fronts a highway, so in a designated area the siting question is about walls, not the roof. A designation does not, on its own, mean you need consent — though a conservation officer may still have views on a prominent roof, and the prior-approval check on larger arrays looks at appearance and glare.

If your barn is a converted dwelling rather than a working agricultural building, a different class applies: a house uses Class A of Part 14, not Class J. A roof array is permitted development provided it does not protrude more than 0.2 m beyond the roof slope or rise above the highest part of a pitched roof (on a flat roof, no more than 0.6 m above it). In a conservation area or World Heritage Site only panels on a wall, balcony or roof enclosure that fronts a highway lose the right — roof slopes are not restricted. A flat-roof array in a conservation area, National Park, National Landscape, the Broads or a World Heritage Site needs a prior-approval application before you start. A building in the curtilage of a listed dwelling already sat outside Class A, and from 27 August 2026 the listed dwelling itself does too, so a listed converted barn will need planning permission as well as Listed Building Consent. A transitional provision lets a roof array that was permitted before that date go ahead without planning permission until the end of 26 August 2027, but Listed Building Consent is needed either way.

How to confirm your barn’s status — step by step

You can establish where your barn stands in an afternoon:

1. Check whether the building is listed. Search the National Heritage List for England, or its devolved equivalents in Wales, Scotland and Northern Ireland. Remember that listing can extend to a building’s curtilage, so a barn within the grounds of a listed farmhouse may itself be caught even if it is not individually listed.
2. Check for a conservation area, a landscape designation or an Article 4 direction. Your local planning authority’s online map will show conservation-area boundaries, National Park and AONB extents, and any Article 4 directions in force. The first two do not remove the right to put panels on an unlisted barn roof; an Article 4 direction might, so read what it names.
3. Confirm the roof geometry. Measure the pitch and confirm an in-plane array will sit within 0.2 m of the roof plane and at least 1 m in from the roof edge. This is usually fine on a standard portal-frame barn.
4. Work out the size of the array. Up to 50 kW is straight permitted development. Over 50 kW, apply to the council for prior approval before you start; you can begin once it tells you approval is not required, gives its approval, or 56 days pass with no decision.
5. Apply for a Lawful Development Certificate if you want certainty. Where a scheme is permitted development but you would like cast-iron proof — useful for a future sale or a nervous lender — you can apply to the council for a certificate confirming the works are lawful. It is not a planning application; it simply documents that none is needed.

A short call with the local conservation or planning officer at the start often saves weeks later, particularly on anything that might be borderline.

What about the rest of the project?

Planning is only one of the consents a barn array touches. The structural appraisal confirms your purlins and frame can carry the modest PV dead load. The G99 grid-connection application to your DNO is usually the longest single step on a rural network, so it is worth submitting early. And if the roof is old asbestos cement, it cannot take panels at all until it has been stripped and re-clad — a separate but related workstream that belongs inside the same project.

This is exactly the territory our sister site solarpanelsforfarmbuildings.co.uk covers for the wider range of agricultural structures, from grain stores to general-purpose sheds, where the same permitted-development logic applies.

Who handles the application

Most barn owners never have to fill in a planning form, because their roof is permitted development — though anything over 50 kW needs a prior-approval application first. For the minority where full consent is needed — a listed threshing barn, a barn in the curtilage of a listed house, a building under an Article 4 direction — a competent installer or a planning consultant manages the whole application: the drawings, the design-and-access or heritage statement, and the conversation with the conservation officer.

Either way, the first thing to do on any barn is confirm its planning status, so you know before you commit whether your roof is a five-minute desk check or a consent that needs designing for.

Want to know exactly where your barn stands? Request a free feasibility check for a first read on your planning position, structure and grid options before you spend a penny.