Designated land and householder permitted development

Designated land does not switch off householder permitted development. It removes specific rights, class by class, in Part 1 of the General Permitted Development Order 2015, and reduces others. On designated land you lose the two-storey rear extension, the roof dormer, the side extension and exterior cladding, and the larger home extension allowances drop back to the standard limits. Everything else in Part 1 survives, subject to its usual conditions.

The term the Order uses is article 2(3) land, and it covers conservation areas, National Parks, the Broads, National Landscapes (formerly areas of outstanding natural beauty) and World Heritage Sites. Listing is a separate matter entirely.

What the Order counts as designated land

Article 2(3) points to the land listed in Schedule 1 of the Order. Five categories, and nothing else: a conservation area, an area of outstanding natural beauty (now called a National Landscape), an area specified by the Secretary of State under the enterprise zone and similar provisions, the Broads, and a National Park or a World Heritage Site.

Note what is missing. A site of special scientific interest is not article 2(3) land for these purposes. Neither is a green belt, a flood zone, an archaeological priority area or a locally listed building. Each of those brings its own consequences, but none of them touches Part 1.

Being in the setting of a designated area does not count either. The boundary is the boundary, and it is usually drawn tightly around the historic core. Check it on the council's own mapping before you assume anything, because conservation area boundaries have been extended and reduced over the decades and older plans circulate freely. Background on the designation itself is covered in the note on article 2(3) land and permitted development in protected areas.

What Class A loses

Class A covers the enlargement of a house. Three restrictions bite on article 2(3) land.

Cladding goes first. On designated land you cannot use Class A to clad any part of the exterior with stone, artificial stone, pebble dash, render, timber, plastic or tiles. That catches the common retrofit of rendering a tired rear elevation, and it applies to the whole house rather than just the extension.

Side extensions go next. Any enlargement extending beyond a wall forming a side elevation of the original house needs permission on designated land, however modest.

And the two-storey rear extension goes. On article 2(3) land an enlarged part that has more than a single storey and extends beyond the rear wall of the original house is not permitted development.

The larger home extension route is also closed. The prior approval scheme allowing a single-storey rear extension of up to eight metres on a detached house, or six metres otherwise, does not apply on designated land, so the depth limits stay at four and three metres respectively. Anyone relying on the neighbour consultation procedure should read the note on the 56 day prior approval deadline before counting on it in a conservation area.

Roofs, dormers and rooflights

Class B, the enlargement of a roof by a dormer or a rear box, is not available at all on article 2(3) land. This is the single change that catches most loft conversions in conservation areas.

Class C survives. Alterations to a roof that do not protrude more than 150 millimetres beyond the plane of the existing roof slope and do not exceed the highest part of the roof remain permitted, which is why rooflights are the standard designated-land loft solution. A conservation rooflight sitting flush in the slope is doing the work a dormer would do elsewhere.

Where a dormer is unavoidable, you are into a full planning application and, in a conservation area, an assessment of whether the roofscape contributes to the character of the area. That is a Heritage Statement question, and the answer usually turns on whether the roof slope is visible from the street.

Outbuildings, hard surfaces and the small classes

Class E outbuildings remain available, with one designated-land restriction that surprises people. Where any building, enclosure, pool or container sits more than 20 metres from any wall of the house, the total ground area covered by such structures must not exceed 10 m². On a large plot in a National Park that limit arrives quickly.

The general Class E rules still apply on top: nothing forward of the principal elevation, single storey, eaves no higher than 2.5 metres, and a 2.5 metre height limit within two metres of a boundary.

Class F hard surfaces are unaffected by designation, though the permeable surfacing rule for front gardens over five square metres applies everywhere. Class D porches survive. Class G flues and chimneys are restricted: on designated land a flue must not be fitted to a wall or roof slope that fronts a highway. Class H antennas and dishes carry their own designated-land limits on size, number and position.

National Parks, the Broads and National Landscapes

The five categories are treated identically by Part 1. A house in a National Park has the same reduced householder rights as a house in an urban conservation area, which surprises rural owners who expect the countryside to be more relaxed.

National Parks and the Broads carry one extra provision elsewhere in the Order affecting larger extensions to dwellings in Part 1 Class A, and the authorities themselves are the local planning authority, so their design guidance and validation lists apply.

World Heritage Site designation covers the inscribed area, not the buffer zone, for Part 1 purposes. The buffer zone matters to the planning judgement on an application, but it does not remove permitted development rights.

Article 4 directions on top

A council can go further by making an article 4 direction that withdraws named classes across a defined area. In conservation areas these commonly remove Class A extensions, Class C roof alterations, Class F hard surfacing to front gardens, window and door replacement, and the painting of exteriors.

Directions are specific. Two adjoining conservation areas in the same borough can have entirely different ones, and the text of the direction is what matters, not the summary on a web page. Ask the council for the direction itself and read which classes it names.

Where a direction applies, the application fee for development that would otherwise have been permitted is not charged, which is a small mercy.

Confirming the position before you build

The only formal way to confirm that works are lawful is a lawful development certificate under section 192 of the Town and Country Planning Act 1990. An email from a duty planner is helpful and is not a defence.

Do the checks in this order: is the site in one of the five categories, is there an article 4 direction, is the building listed, has the house been extended before, and does the proposal fall within the surviving class. The allowance question is the one people get wrong most often, and the note on what original dwellinghouse means in the GPDO explains why a 1970s conservatory can consume most of it.

Where a right has been removed, the application that follows is a design argument rather than a rules argument. Enter your postcode on PlanScope to see which supporting documents the council is likely to expect.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. A lawful development certificate is the only formal way to confirm that works are lawful. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.