What permitted development allows.

The householder allowances (the rear extension, the loft, the garden room) belong to dwellinghouses and the order says plainly that a dwellinghouse does not include a building containing one or more flats, or a flat within such a building. Some permitted development rights are not tied to houses and can still apply to a block of flats, such as walls, fences and gates within their limits. One class also lets the owner of a detached, purpose-built block of three or more storeys add up to two storeys of flats, with prior approval. But a leaseholder hoping to extend under the householder rules has none to use.

A direction is made by the council or the Secretary of State. In a conservation area a council can give one immediate effect for changes facing a road or open space, such as windows, doors and roofs. The Framework's examples include preventing too many small houses in multiple occupation. The Framework of August 2026 says a direction should be limited to situations where it is necessary to protect local amenity or the wellbeing of an area, be based on strong evidence and apply to the smallest area needed (policy DM10). A direction is publicised when it is made, with a place where it and its map can be inspected. It applies to the land, so it binds every later owner.

The order expressly gives way to such a condition. The Framework says conditions should not restrict national permitted development rights unless there is clear justification (policy DM6), but both barns on this page with full planning permission carry one; on the fertiliser barn neither we nor the council wanted the settled design altered by right. The condition is written on the decision notice of the permission that created the house, not in your title deeds, which is why it is easy to miss. It can be challenged by an application to vary or remove the condition, decided on the planning merits at the time of that decision.

Permitted development can be built without one and that is lawful. A certificate earns its fee where someone else will rely on the answer: a buyer's solicitor, a lender or a neighbour likely to complain. It is decided on the drawings and the facts, not on whether the council likes the design. It describes the project as drawn on the day you apply, so build what was certified. More on how certificates work is in the guide to lawful development certificates.

The same narrower householder rules apply in an area of outstanding natural beauty (now known as a National Landscape), a National Park, the Broads and a World Heritage Site. On those four, garden buildings more than 20 metres from the house are also capped at 10 square metres in total. On all of that land, conservation areas included, garden buildings may not go between a side wall and the boundary. A council can add an Article 4 direction on top to bring windows, doors and roof coverings under control. Separately, most work to a tree in a conservation area needs six weeks' notice to the council, or consent if it has a preservation order, even when the project is permitted development. The more designations a site carries, the more worthwhile it is to check the position in writing before drawing anything.

Within 2 metres of a boundary it may be no more than 2.5 metres high. Further from the boundary the limits are 4 metres with a dual-pitched roof and 3 metres for any other roof, with eaves no higher than 2.5 metres. Garden buildings and extensions together may not cover more than half the curtilage, leaving out the ground the original house stands on. Incidental means uses such as a store, a shed or a garage for the household; government guidance says a bedroom, bathroom or kitchen is not incidental. A separate home is a change of use the rights do not cover. Nothing may be built under these rules within the curtilage of a listed building.

Class Q converts farm buildings and Class MA converts commercial ones. Other classes add storeys of new homes on top of certain blocks of flats, commercial buildings and houses; one allows a vacant building of a set age and type to be demolished and replaced by homes, within limits on footprint and height. Every one runs through prior approval. A field, a garden plot or a cleared site has no permitted development route to a new home and needs planning permission.

Adding storeys is the other common case where neighbours are consulted. For a larger single-storey rear extension the council notifies the adjoining owners and, if one of them objects, decides whether the extension's effect on their amenity is acceptable. For most other projects neighbours have no formal say: permitted development rights are granted nationally and a project inside them is lawful whatever a neighbour thinks of it. A neighbour can still ask the council to investigate a project they believe breaks the limits, which is one good reason to keep the measured drawings or a certificate.