The rule that rules out most timber balconies

What changed, and the year you have to decide

On 27 August 2026, the same day the law changed, the permitted development right for solar equipment on a house, a block of flats or a building within the curtilage was updated. A year of grace runs to 27 August 2027, and until then the Planning Portal says you may work to whichever version suits you, the one that stood the day before the change or the one that replaced it.

The wooden surface exclusion

Under the new rules, for houses and for blocks of flats alike, the Planning Portal lists a prohibition on wooden wall, balcony and timber-clad installation, and annotates it as applying to plug-in solar.

Read that against how the product is marketed. Almost every advert, review and vendor guide in the country calls this balcony solar, and a very large number of British balconies are timber or timber clad. If yours is, permitted development does not cover it, and you would be applying for planning permission for a device that costs a few hundred pounds.

The limits that apply everywhere else

Houses, wall facing a highway

Projection of no more than 200 mm.

Houses, other surfaces

Projection of no more than 400 mm.

Pitched roofs

Below the highest part of the roof, no more than 200 mm projection.

Flat roofs

No more than 600 mm above the roof in England. Wales differs.

Conservation areas and World Heritage Sites

Not on a wall that fronts a highway.

Listed buildings and scheduled monuments

Planning permission and listed building consent. Take advice before ordering.

Source: Planning Portal. These are the England rules. Wales sets its own, and they are not the same.

Wales is not the same

If you are in Wales, two of the numbers above are different, and the Welsh guidance does not mention plug-in solar at all.

Flat roofs

Panels must not be within 1 metre of the roof edge, and must not project more than 1 metre above the roof plane.

Standalone panels

One only. Maximum height 4 m, or 2 m within 5 m of the boundary. At least 5 m from the highway. Maximum 3 m across and 9 square metres.

Flats

The Welsh guidance simply advises contacting your local planning authority.

Plug-in solar specifically

Not addressed. There is no Welsh equivalent of the English wooden surface exclusion, and no equivalent 27 August change.

Source: gov.wales. Because the Welsh guidance is silent on plug-in solar, we will not tell you it is permitted there. It is not settled.