What a conservation area restricts.

Section 69 of the Planning (Listed Buildings and Conservation Areas) Act 1990 requires every council to decide which parts of its area meet that test, designate them, and review them from time to time. The Framework of August 2026 adds that a new or amended area should come with an adopted appraisal and management plan, and that a place lacking special interest should not be designated at all. Designation is a local land charge, so it appears on the local search when a property changes hands. What designation changes in practice is set out in section 02.

Householder permitted development lives in Part 1 of the permitted development order. In a conservation area that Part is amended rather than switched off. An enlarged part may not extend beyond a side elevation wall of the original house. A rear extension of more than a single storey is not permitted, and nor is the larger single-storey rear extension that needs prior approval. Roof enlargements, dormers included, are not permitted at all, and nor is cladding the exterior. The ordinary depth and height limits still apply, so a single-storey rear extension within them is as available here as anywhere. What changes is that the easy answers run out sooner and a scheme that would have been automatic on an ordinary street becomes a planning application.

Work that only affects the interior, or that does not materially affect the external appearance of a building, is not development at all, which is why like-for-like window repair and replacement generally needs nothing. Timber to plastic is a different proposition, because the external appearance plainly changes, and it is precisely the change that conservation areas are designated to control. That is why windows are the single commonest subject of an Article 4 direction: authorities withdraw the right specifically so that replacements have to be applied for. Flats and maisonettes never had householder rights in the first place, so any external alteration to one that changes its appearance needs permission wherever it is.

The permitted development order lists the materials caught: stone, artificial stone, pebble dash, render, timber, plastic and tiles. Cladding any part of the exterior of a house with any of them is not permitted development on conservation area land, which means an application is needed even where the same work two streets away would need nothing. It is one of the restrictions people discover after the scaffold is up. Painting is a different question and usually falls outside development altogether, although a direction can catch that too, and on a listed building any of it may need listed building consent regardless of what the area designation says.

Designation of a conservation area on its own only narrows permitted development in the ways the order itself sets out. Where an authority wants to go further, in a place where it can show the character of the area depends on it, it makes a direction. Windows and doors, front boundary walls, roof materials, porches, hard standing and satellite dishes are the usual subjects. A direction does not ban the work: it removes the right to do it without asking, so the work becomes an application like any other. Directions are published by the authority and are the single most important thing to check before assuming anything, because two houses on the same street can fall under different ones.

A building can be in a conservation area, listed, both or neither. The consequences are entirely different. Listing brings the whole building under control, inside and out, including alterations that affect its special interest. Work affecting that interest needs listed building consent on top of any planning permission. Designation of an area brings no such control over an individual unlisted building: what it does is narrow permitted development, catch demolition, protect trees and place a duty on the council when it decides applications. The confusion costs real money in both directions, either through applications nobody needed or through work carried out on a listed building without the consent it required.

The duty a conservation area places on a council concerns the character and appearance of the area and the inside of an unlisted building contributes to neither. So a building can be gutted, reordered, re-planned and refitted without the designation having anything to say about it, provided nothing outside changes and nothing is demolished. That is worth knowing early, because it often means the ambitious part of a project is the uncontroversial part. The exception is listing, which reaches inside, and building regulations, which apply to internal work wherever it is and are a separate approval with their own timetable.

Carrying out relevant demolition in a conservation area in England without the planning permission it requires is an offence under section 196D of the Town and Country Planning Act 1990, punishable on summary conviction by imprisonment of up to twelve months or a fine; on indictment, by up to two years, with the court required to have regard to any financial benefit that resulted. Other breaches are not criminal, but enforcement action can be taken within ten years of the breach in England, a period that was raised from four years for building operations on 25 April 2024. Where work has already happened, a retrospective application is an ordinary application decided on ordinary grounds and it is much cheaper than an enforcement notice.