Permitted development in conservation areas — exactly which rights you lose

The most common misconception we hear on site visits: 'we're in a conservation area, so nothing is permitted development.' Not true — and the opposite assumption ('PD applies everywhere') is just as costly. Conservation-area status, as 'article 2(3) land' in the legislation, edits the permitted development order line by line. Knowing exactly which lines is the difference between a certificate and a refused application.

What survives in a conservation area

Single-storey rear extensions within the basic limits — 3m attached / 4m detached, under 4m high (Class A survives, trimmed).
Rooflight-only loft conversions that don't change the roof plane (Class C, on most houses).
Rear outbuildings — garden rooms and sheds within Class E limits.
Like-for-like repairs and maintenance, internal works to unlisted buildings, most decoration.

What designated land removes

The larger home extension (6m/8m prior approval route) — excluded entirely.
Side extensions — no PD route at all on designated land.
Rear extensions of more than one storey — full permission required.
Roof enlargements (Class B) — every dormer and mansard needs an application.
Exterior cladding — stone, render, timber, tiles all need permission.
Chimneys, flues and satellite dishes on walls visible from the street.

Article 4: the second cut

Where a council judges that even the surviving PD rights threaten an area's character, it can make an Article 4 direction removing specific rights street by street — front elevations, windows, roof materials, boundary walls, sometimes the basic rear-extension allowance itself. London uses Article 4 heavily: Hampstead, Muswell Hill and large parts of Westminster all carry directions. The designation is invisible from the street; it lives in the data.

How to know what applies to your house

Conservation areas and Article 4 directions are both published as official geometry on planning.data.gov.uk — which is exactly what the Siteline area check queries. Enter a postcode and it tests your coordinates against the live boundaries for our covered boroughs and cites the dataset. For the legally definitive position (boundaries can be amended), confirm against the council's own conservation-area map or a Lawful Development Certificate application.

Run your postcode through the area check — conservation area and Article 4 status against official boundaries, free, in seconds.

Check an address

Can I still extend my house in a conservation area?

Yes — single-storey rear extensions within the basic PD limits usually remain permitted, and full applications for larger or two-storey schemes are approved constantly where the design respects the area. Conservation status raises the design bar; it doesn't ban extension.

Does a conservation area affect what colour I can paint my house?

Repainting is generally not development and stays outside planning control — unless an Article 4 direction in your area specifically pulls it in, which some London directions do for front elevations. Check the direction's schedule, not just its existence.

Is a conservation area the same as being listed?

No. Listing attaches to a specific building and controls works (including internal) that affect its special interest. A conservation area covers a whole neighbourhood and modifies the planning rules for everyone in it. A house can be both — then both regimes apply.

How do I find out why my street was designated?

Every conservation area has a designation report or character appraisal published by the council. It's worth reading before designing: officers assess applications against the character it describes, so it's effectively the design brief.

Permitted development in conservation areas: what you lose and why