The permitted development rules, in plain English
On a house, roof-mounted panels are permitted development provided they do not protrude more than 20cm from the roof slope, do not sit higher than the ridge, and, so far as practicable, are placed to minimise their look from the street. Ground-mounted arrays are also permitted within limits: broadly one array, up to 9 square metres and no taller than 4 metres, kept away from boundaries.
Permitted development means you do not apply for planning permission; it does not mean nobody is involved. The installation must still meet building regulations for the roof loading and the electrics, which is part of what a competent installer certifies, and your electricity network operator is notified about the connection, which MCS-certified installers handle as part of the job.
The exceptions that catch people
Flats and maisonettes do not get householder permitted development rights, so panels on a block generally need permission and the freeholder's consent. Listed buildings need listed building consent for panels anywhere on the property, including outbuildings, and consent is far from automatic. In conservation areas the rules tighten rather than vanish: roof panels are usually still permitted on rear slopes, but panels on a wall facing the street are not, and local Article 4 directions can remove the rights entirely.
The five-minute check that settles it: your council planning portal will say whether you are in a conservation area or covered by an Article 4 direction, and the listed building register is searchable online. Do it before the survey, because a good installer will ask.
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For the typical semi with a pitched roof, the answer is that planning adds nothing: no cost, no delay, and any installer telling you otherwise is padding the job. Where consent is needed, a planning application typically runs a few hundred pounds with an eight-week determination, and that belongs in your timeline rather than as a surprise after the deposit.
Either way the practical sequence is the same: check your status on the council portal, then compare quotes from MCS-certified installers and tell them what you found. How the system itself should be sized is covered in how many panels you need, and the export paperwork in the Smart Export Guarantee.
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Up to three trusted, MCS-certified installers quote for the work. Free, no obligation.
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