Full Planning Permission Explained: When You Need It

Full planning permission is needed whenever your project goes beyond what permitted development allows. In London, that covers a large share of ambitious home projects: mansard roofs, most double storey extensions, side return and wraparound extensions on many streets, work to flats, and almost anything in a conservation area. Getting it right first time is one of the biggest factors in how quickly your project can start.

When you are likely to need it

• Extensions larger than permitted development limits, or of a type not covered
• Mansard roofs and front facing roof alterations
• Any extension or external alteration to a flat or maisonette
• Work in conservation areas or areas covered by an Article 4 direction
• New buildings, new dwellings and splitting a house into flats
• Most changes of use

Projects to houses are usually submitted as a householder application; flats, new dwellings and commercial schemes use a full application. Listed buildings also need listed building consent.

How the process works

1. Pre application advice (optional): many London councils offer paid advice before you apply. Useful for sensitive sites.
2. Submission: drawings of the existing and proposed building, a site location plan, the application form and fee, plus any supporting documents such as a design and access or heritage statement.
3. Validation: the council checks the application is complete before the clock starts.
4. Consultation: neighbours are notified and can comment, usually for 21 days.
5. Assessment: a planning officer visits and weighs the proposal against local and national policy.
6. Decision: the target is eight weeks for householder and minor applications, thirteen for major schemes, although some councils run late.

After the decision

Approvals come with conditions, often on materials, and some must be discharged before work starts. Permission usually lasts three years. If refused, you can amend and resubmit, or appeal. Householder appeals generally have to be lodged within 12 weeks of the decision.

How to improve your chances

• Read your council’s design guidance for extensions, lofts and conservation areas.
• Look for approved precedents on your street.
• Present clear, accurate drawings that answer the officer’s likely concerns.
• Talk to neighbours before they receive the consultation letter.

How we handle planning on London’s Prestige projects

We work with experienced designers to prepare drawings that reflect how London councils assess applications, track the application through to decision, and build discharge of conditions and lead in times into your programme so the build can start as soon as approval is in place. Our Corbyn Street loft and extension shows the kind of project we take from approval to handover. Read our guide on planning permission for London extensions, explore our extension service, and book a site visit to talk through what your project will need.