Planning Permission for Solar Panels

The main considerations for installers and for customers wishing to install solar panels on their homes are:

“Panels should not be installed above the highest part of the roof (excluding the chimney)”

This is easily achievable and standard practice for pitched or sloping roofs. Solar panel design engineers will design solar systems to fit on the roof and not extend beyond the ridge.

Micro-Generation Certification Scheme (MCS) recommends leaving a 300 – 400 mm gap between the top of the array and the ridge of the roof. This is to avoid putting pressure on your roof and panels from wind, so there are multiple reasons to conform to this guidance.

“[Solar panels] should project no more than 200mm from the roof slope or wall surface.”

Again, for sloping roofs it is standard practice to install panels under 200mm from the slope of the roof. Solar mounting frames used to attach solar panels to pitched roofs are low profile and the panels won’t project more than 200mm from the roof slope.

Solar panels mounted on a residential roof sit less than 200mm above the surface.

Solar panels on a flat roof with a low angle to conform to permitted development (less than 200mm from the plane of the roof).

Installing solar panels on flat roofs normally falls just outside of permitted development, as the panels can project slightly higher than 200mm from the roofline.

If you would like to fit solar panels to a flat roof, there are various options:

1. Apply for planning permission. We’d recommend contacting an architect or planning consultant to apply on your behalf. They’d need to produce scale drawings of your house and submit supporting documentation. Architects would charge around £1,000 – £3,000 for the application. These applications take at least 2 months from submission to get approval.
2. If we opt for a mechanically fixed mounting system (that is a system that is fixed to your roof rather than weighed down), we can angle the panels at 5% so that they are under 200mm from the roof.
3. On the whole, we have found planning departments to be quite supportive of solar panel installations on flat roofs and as of August 2023, there is a consultation to allow more leniency for solar panels on flat roofs (as the permitted development is geared towards pitched roofs).  If successful, this would open up the possibility of installing using a wider range of mounting systems, that sit at a slightly higher angle, without the need for planning permission.

There are a different set of rules for planning permission on commercial buildings.  The height above the roof requirement of 200mm still applies, and standard mounting systems will all comply with this.

At the edges, base and apex of the roof a gap of 1m must be left.  For large metal roofs, this requirement is sensible from  a wind-loading perspective and to allow space for scaffold edge protection during the build and a safe working environment.

For smaller tiled roofs on commercial properties, such as you might find on schools or offices, leaving 1m perimeter can limit the installed capacity of solar panels, and make systems look a little peculiar.  In these cases, we’d recommend an informal conversation with the planning department.

Commercial solar PV installation showing 1m boundary between panels and the roof edge.

Solar Panels fitted to a loft conversion roof. In-roof panels on the pitched roof section and mechanically fixed panels on the flat roof section.

The short answer is yes. Fitting solar at the same time as getting a loft conversion makes a lot of sense. It can’t hurt to include the solar panels on the planning application for a loft conversion, if you think you might want solar panels.

Loft conversions often include an installation of a new, rear dormer roof to increase headspace in the loft room and flat, dormer roofs are a great place to fit solar panels as they are normally hidden from the street at the back off the house. It’s also possible to fit panels on the front sloping section of roof at the same time.

If your roof is getting re-slated or tiled, you can save on slate by fitting in-roof solar panels.

Yes. If your property is listed, you will need planning permission and listed building consent.

As the guidance states:

“The panels must not be installed on a building that is within the grounds of a listed building or on a site designated as a scheduled monument.”

Normally, listed buildings are sensitive and will require particular care in designing and applying for planning and listed building consent. We’d recommend contacting an architect or planning consultant if your house is listed, as they will give you the best chance of getting approval.

There are a number of design considerations that can help here.  Using all-black panels, instead of conventional modules with a silver frame and white backing, will help your project be seen more favourably from a conservation perspective.

We have installed on listed buildings many times, including Salisbury Cathedral and royal palaces.

Ground mounted solar panels require planning permission in most cases.

The short answer is yes, you do need planning permission for most ground mount solar arrays.

Very small arrays are considered permitted development, but “the size of the array should be no more than 9 square metres or 3m wide by 3m deep”.  In practice this would only allow an array of 4-5 panels, which would not be economically worth it in most cases.

An alternative is to install a moveable ballasted system such as this one, which can be considered a temporary structure and therefore doesn’t need planning permission.

Some customers have been happy to submit the application themselves while others prefer to use an architect or planning consultant.

If you are not already in touch with an architect or planning consultant, we can recommend one to you.