Solar Panels on Listed Buildings and in Conservation Areas

Can a listed business building have solar panels?

Yes, in many cases, but the law treats it as works to the listed building. In England, no one may carry out works that alter a listed building "in any manner which would affect its character as a building of special architectural or historic interest" unless they are authorised by listed building consent (section 7), and doing so without consent is an offence (section 9).

The council's conservation officer is the person to talk to early. Planning permission is usually needed as well as listed building consent. More on the general rules: planning permission for business solar.

Listed building consent: what to expect

Cadw's guide to micro-generation on historic buildings sets out what councils look for (Cadw):

• Inside and out. Controls apply to internal and external works, whether or not the feature affected is mentioned in the list description, so cable routes and inverter positions count too.
• The curtilage. Protection usually extends to structures fixed to the building or within its curtilage, which may include ancillary buildings, garden structures and boundary walls.
• A design and access statement. The application explains why this system and this position were chosen over the other options, based on their impact on the historic building.
• Setting. The effect on the setting of the historic property is a material consideration, so a ground array in view of the building is judged too.
• Scheduled monuments. Any works to a scheduled monument need scheduled monument consent as well.

A grant offer doesn't replace consent: Cadw says not to assume you won't need further permissions just because a grant has been offered.

Conservation areas

A conservation area doesn't remove the permitted development right for solar on a business roof, but each nation adds limits:

Councils can also remove permitted development rights with an Article 4 direction, most often in conservation areas (GOV.WALES), so check before you start.

Placing panels out of sight: outbuildings, ground and carports

Cadw's guide gives the order to try things in (Cadw):

• Away from the building. Install solar panels as free-standing units if possible, with a dark frame and some planting to soften them.
• Less prominent parts. If not, use hidden roof valleys, rear extensions, or a flat roof behind a parapet wall.
• Not the front. Unless the panels can be screened, avoid principal elevations and prominent roof slopes.
• Reversible. Choose cable routes that cause the least damage even if they are less direct, use existing conduits where possible, and keep alterations easily reversible.

For many listed sites the answer is a newer outbuilding (still within the curtilage, so still asked about), a ground array or a canopy over the car park. A ground array of business size needs a planning application anyway. See ground-mounted solar and solar carports.

Old roofs, structure and fire

Older roofs need more care. The MCS solar standard requires (MIS 3002):

• A structural check. The roof structure is checked by a competent person, and a qualified structural engineer is consulted where the roof is unusual, shows signs of distress or has been altered, or there is any doubt.
• Weather tightness. The system must not affect the building's weather tightness or structural integrity for its whole life.
• Roof warranties. Where the roof covering is under warranty, the warranty provider is consulted first.

Historic roofs with lead, slate or old timbers may also need a specialist. Fire is the other question insurers ask about; see fire risk and insurance. Churches have their own permission system: see solar for churches.

What the survey checks on a listed or historic site

• Status. Whether the building is listed, and at what grade; whether it is in a conservation area or under an Article 4 direction; what else is in the curtilage.
• Where panels could go. Every roof slope, outbuilding, flat roof, car park and patch of ground, ranked by how visible it is and how much it would produce.
• Structure and fabric. Roof timbers, coverings and any lead, and how fixings and cables would be routed with the least damage.
• Your daytime use. How much of the output you would use, which decides whether a smaller, hidden array still pays.
• Paperwork. What the consent application needs, so you can talk to the conservation officer with real drawings.