Free Westminster permitted development checker

What are you checking?

Whether your proposed work may qualify for permitted development, needs a prior approval process or requires a planning application. The property and the complete proposal matter, including earlier additions and conditions on previous permissions.

Read how prior approval works and how planning timescales differ by route.

A postcode locates an area; it cannot establish rights for a particular house. Use your full property address in the checker.

Find guidance for your project

• Rear extensions and larger home extensions
• Side and wraparound extensions
• Loft conversions and dormers
• Garden rooms and outbuildings
• Garage conversions
• Porches
• Two-storey extensions
• Basements

For development beyond a home improvement, read our new build and change of use guides. Those projects have different eligibility tests and need a project-specific assessment.

Local checks in Westminster

Check the wording, map and effective date of any Article 4 direction, the property's planning conditions and whether designated land affects the relevant right. A restriction on one type of work does not automatically prohibit every alteration.

Use these resources for Westminster. Confirm the authority for your address if you are close to a boundary or the area has changed council.

• Westminster official website and planning information
• Search Westminster planning applications and decision notices
• Westminster planning authority boundary and source
• Find the planning authority for your postcode

We have not verified every local restriction for every address in Westminster. Confirm property-specific details against the authority's current records before relying on permitted development.

Our Westminster archive contains 23,629 classified home project decision records. Explore Westminster decisions by project type. These records mix application routes: an approval rate is not a permitted development eligibility score. See the coverage and methodology.

Permitted development restrictions in Westminster

Westminster has a city-wide basement Article 4 direction alongside directions for specified alterations in particular conservation areas and for changes of use. Its interactive map allows an address search. Check the relevant notice and map; basement controls and a street's alteration controls address different works.

• Westminster Article 4 directions and address map
• Westminster conservation areas and audits
• Westminster current validation list and supporting reports
• Westminster conservation audits and guidance, L to Z

Sources reviewed 5 September 2026. Check the source maps, wording and effective dates against your property and proposed work.

Check the address and the work, not just the conservation area

Westminster's city-wide basement direction took effect on 31 July 2016. Separate directions cover specified alterations at places including Queen's Park Estate, Abbey Gardens and parts of Bristol Gardens. Search the address map and read the applicable schedule: a direction covering one type of work does not remove every permitted development right. Read the council guidance.

Check the property's planning history

Householder extension rights do not apply to flats. Westminster also warns that a previous permission may contain conditions restricting permitted development. Review the decision notices for your property, as well as Article 4 directions, before relying on a national size limit. The council recommends a lawful development certificate to confirm qualifying works. Read the council guidance.

What reviewed local decisions show

These examples use official planning records. Each identifies the decision date and links to the evidence reviewed. They are not Planning Approvals projects or a prediction for another property.

• 31 Bloomfield Terrace: approval with limits on later alterations

  24/08116/FULL and 24/08117/LBC · Committee resolved to grant with conditions, 18 March 2025

  The committee voted to grant permission and listed building consent for a new house beside the terrace. The minutes record added historic-wall protection requirements and a condition requiring written permission for later enlargement or material external alteration despite householder permitted development provisions.

  What to check: Read the conditions attached to the specific permission. A new house is not necessarily free to use the usual extension rights later, and this complex listed-building case is not a comparable simple house extension.

  Read the committee decision · Read the officer report (PDF)

  Related guidance: New-build planning permission · Permitted development

Check the planning register for the issued notice, exact conditions and any later appeal or revised application. A committee resolution is not a substitute for those documents.

Certificate records to investigate

We do not have a suitable certificate excerpt to display here. Use the council register to look up your address and comparable projects.

A certificate concerns the lawfulness of the scheme described. Another property's certificate does not establish your permitted development rights. Read the archive's coverage and limitations.

Do you need a permitted development certificate?

A proposed lawful development certificate gives formal confirmation that the development described is lawful. It is optional and is different from prior approval or a planning application. Read our lawful development certificate guide.

The free check does not grant permission or replace a certificate. Check official certificate guidance and the government's explanation of planning routes.