Knowledge Base
Planning, regulations and construction, explained.
Topic 02
Do I need planning permission?
Understand when planning permission, prior approval or a Lawful Development Certificate may be relevant to your project.
19 articles
The basics
01Do I need planning permission? How to tellYou need to apply for planning permission when the proposed work is development and no existing permission, permitted development right or other lawful route covers it. Check the property, the complete design and any restrictions before relying on a general size allowance.02Planning permission vs building regulations: what's the difference?Planning permission controls whether development is acceptable in its location; building regulations set technical requirements for the building work. A project may need both, and approval under one system does not approve it under the other.03What is permitted development?Permitted development is planning permission granted nationally for specified types of work, subject to limits and conditions. It can remove the need for a normal planning application, but does not remove all paperwork or other approvals.04Does my property have permitted development rights? Houses vs flats and maisonettesThe usual householder rights for extensions and roof enlargements apply to qualifying houses, not flats or maisonettes. Ownership of the garden or a share of the freehold does not turn a flat into a house for those rules; other permitted development rights must be checked separately.05What counts as the "original house", and have previous owners used up my allowance?The “original house” is the house as it stood on 1 July 1948, or as first built if it was built later. Earlier owners’ extensions and roof enlargements can still affect what you may add; buying the property does not reset the allowances.06Have my rights been removed? Article 4 directions and old planning conditionsYour council can remove particular permitted development rights through an Article 4 direction or a condition on a planning permission. Check the actual wording, mapped area and effective date: a restriction usually means that an application is needed, not that the work is automatically prohibited.07Where do I measure from? Heights, depths and boundaries explainedPermitted development measurements use defined reference points, including the original house, adjacent ground level and the boundary of its curtilage. A dimension from an estate-agent plan, the current back wall or the top of a fence may answer the wrong question.08Principal elevation, side elevation, eaves: the terms that decide what's allowedTerms such as principal elevation, original house and eaves have specific meanings in permitted development guidance. They determine which walls, roof lines and measurements count, so labelling a drawing “front” or “rear” does not settle the legal test.09Permitted development changes in the news: what's proposed vs what is actually lawA permitted development announcement changes your rights only when the relevant legislation takes effect, with any conditions and transitional rules. As checked on 2 October 2026, recent heat-pump and solar amendments are in force, while further proposals must not be treated as permission to build.
Prior approval
10What is prior approval, and how is it different from planning permission?Prior approval is a procedure attached to some permitted development rights: national legislation grants the permission, while the council checks the matters specified for that particular right. It is not an unrestricted planning application, and the required process must be completed before starting.11Larger home extensions: building a 6m or 8m rear extensionA qualifying house can use the larger home-extension route for a single-storey rear extension up to 6 metres deep if attached, or 8 metres if detached. The prior-approval procedure must be followed before work starts, and the extension must meet all the other permitted development requirements.12Neighbour consultation: what happens when neighbours object to a 6m/8m extensionA neighbour’s objection does not automatically stop a 6-metre or 8-metre rear extension. Under the larger home-extension procedure, an objection from an adjoining owner or occupier triggers the council’s assessment of the effect on adjoining amenity; it is not a vote on whether you may build.13Adding a storey to your house (Class AA)Part 1 Class AA can allow one additional storey on a qualifying single-storey house, or up to two on a house with two or more storeys. Eligibility is tightly limited, and written prior approval is required before work begins: an unanswered application does not authorise construction.14What if the council doesn't decide in time?A missed council deadline does not always mean you can start. The larger rear-extension procedure has a conditional 42-day route, but upward extensions under Part 1 Class AA require written prior approval even when the council is late.
Lawful Development Certificates
15What is a Lawful Development Certificate, and do I need one?A Lawful Development Certificate is a formal determination that the work or use described in it is lawful for planning purposes. It is not always compulsory, but can provide clear evidence where you rely on permitted development or need to establish the status of existing work.16Is a certificate worth getting if my project is permitted development?A certificate is often worth considering when a permitted development project needs a dependable planning record, particularly before substantial work or a later sale. Its value is formal evidence of lawfulness, not a guarantee that every aspect of the project is approved.17Certificate for proposed works (CLOPUD) vs existing works or use (CLEUD)A CLOPUD concerns work or use which is proposed; a CLEUD concerns work already carried out, an existing use or a specified breach of condition. Both establish planning lawfulness, but they ask different questions and need different evidence.18Certificate or planning application: which route for my project?Use a Lawful Development Certificate to establish that a precise proposal is already lawful under planning law; use a planning application when you need the council to grant permission. Where a permitted development right requires prior approval, follow that procedure rather than treating a certificate as an alternative.19Mixing routes: a permitted development extension next to one with planning permissionIt is possible to use planning permission for one element of a project and permitted development for another, but each must have a sound legal basis and the combined works must be assessed correctly. A separate permission does not automatically exempt an existing or proposed adjoining extension from the permitted development calculations.