Part 14 solar panels on a dwelling: limits and exclusions

Solar panels on the roof of a house are usually permitted development. Class A of Schedule 2 Part 14 of the Town and Country Planning (General Permitted Development) (England) Order 2015 allows the installation, alteration or replacement of microgeneration solar photovoltaic or solar thermal equipment on a dwellinghouse or a block of flats, or on a building within the curtilage, subject to a short list of conditions.

The two that decide most roof installations are the projection limit and the ridge limit. Equipment must not protrude more than 200 millimetres beyond the plane of the wall or the roof slope, measured perpendicularly, and it must not be higher than the highest part of the roof, excluding any chimney.

That rules out tilted frames on a shallow pitched roof and rules in almost every in-plane panel installation. Check the current wording of the Order before you order, because Part 14 has been amended more than once.

Roof mounted panels

For a standard pitched roof, panels sitting on rails in the plane of the slope will clear the 200 millimetre limit comfortably and will sit below the ridge. Nothing further is needed.

Flat roofs are where the right runs out. A ballasted array on a flat roof is normally tilted to about the optimum angle, and once the frame lifts the panel more than 200 millimetres above the roof plane the installation falls outside Class A. The options are a low tilt system that stays inside the limit, an east and west facing configuration with a shallower pitch, or a planning application.

Two further conditions apply to every installation under Class A. Siting must, so far as practicable, minimise the effect on the external appearance of the building and on the amenity of the area. And the equipment must be removed as soon as reasonably practicable when it is no longer needed for microgeneration.

The amenity condition is not usually enforced against a domestic roof array, but it is the hook a council will use where an installation is unusually conspicuous on a prominent elevation.

Wall mounted equipment and designated land

Wall mounted panels are covered by the same class and the same 200 millimetre projection limit. The restriction that catches people is on article 2(3) land.

Article 2(3) land means conservation areas, National Landscapes, areas designated as National Parks, the Broads and World Heritage Sites. On that land, solar equipment must not be installed on a wall which fronts a highway. A side or rear wall is fine. A front wall facing the road is not, and the definition of highway includes an unadopted road and a public footpath, so a house on a corner plot can have two walls fronting a highway.

Roof mounted panels on article 2(3) land are still permitted development under Class A, which surprises people who assume a conservation area removes the right entirely. It does not, though an Article 4 direction can, and several authorities with large conservation areas have made directions that do. Check the council's list of Article 4 directions and the national Article 4 direction dataset before assuming the right survives.

Listed buildings are different. Class A does not permit installation on a listed building, and any work to a listed building or a structure within its curtilage needs listed building consent in its own right. A Heritage Statement assessing significance and the effect of the panels is the document that carries that application.

Standalone arrays in the garden

A ground mounted array in the garden is covered by Class B rather than Class A, and the limits are tighter.

Within the curtilage of a listed building the right does not apply. On article 2(3) land the array must not be nearer to a highway than any wall of the house that fronts that highway, which on most plots pushes it to the rear garden.

Nine square metres is a small array. A domestic ground mount sized to run a heat pump and an electric car will exceed it, so a planning application is the normal route for anything meaningful in a garden. The application is straightforward and turns on visual effect, glint and glare towards neighbours, and the loss of garden space.

When to apply anyway

There are three situations where an application is worth making even though the right exists.

The first is a flat roof where the tilt matters. A shallow angle to stay inside the permitted development limit can cost real output over a year, and permission for a properly angled array is often granted without difficulty on a rear or hidden roof.

The second is a listed building or an unusually prominent position in a conservation area, where a refusal after installation is a much worse outcome than a decision beforehand.

The third is where you want certainty. A lawful development certificate is the only formal way to confirm that works are lawful, and a certificate of lawful proposed development under section 192 of the Town and Country Planning Act 1990 does exactly that for a solar installation. It costs a fee, takes around eight weeks and is the document a buyer's solicitor will ask for. Where a full application is needed instead, a short Planning Statement covering the energy case and the visual effect is normally the only written document required.

What the installer's paperwork does not cover

An installer will normally confirm that the system complies with the microgeneration certification scheme requirements and that the electrical work meets the relevant standards. That is not a planning assessment and it is not building control.

Structural adequacy of the roof is a building regulations matter and is separate from planning. So is fire performance where panels sit on or near a boundary. Where the property is a flat within a block, the freeholder's consent and the terms of the lease usually matter more than the planning position.

Grid connection is the other item to settle early. Distribution network operators apply their own limits to what can be connected without prior approval, and a large domestic array with battery storage often needs an application to the operator regardless of the planning outcome. That application runs on its own timetable and is not affected by anything the council decides.

Battery storage itself is worth a separate thought. A domestic battery inside the house or in a garage is not usually a planning matter, while an external enclosure in the garden can be, depending on its size and position, and the same outbuilding rules that govern a garden store apply to it.

If the panels form part of a wider project, an extension or a loft conversion for instance, deal with them in the same application. A Design and Access Statement that shows the array in the elevations from the start avoids the awkward conversation about equipment that appeared on the roof after the drawings were approved.

This is general guidance rather than legal advice. Check the position with your local planning authority or a qualified professional before relying on it.