Heritage controls attach to designated places and assets, not to a postcode as a whole. This guide sets out how to verify the position for the individual property and distinguish planning permission, listed building consent, Building Regulations, freeholder approval and party-wall matters.
Extension types — single, double, rear, side
When reviewing extension types — single, double, rear, side, ask for advice that is specific to the building and exact address. A useful proposal explains what has been inspected, what remains an assumption, and which parts of the work could affect cost, programme or compliance. That clarity is important for house extension and architect in any period home.
The practical test for extension types — single, double, rear, side is whether it reduces uncertainty before work begins. Good preparation creates a written scope, identifies the approvals or evidence to verify, and makes clear who is responsible for each step before walls, floors or shared services are opened up.
Permitted Development for extensions
Do not infer planning rights from an NW London postcode. Confirm the responsible authority for the exact address, then check current designation maps, Article 4 directions, planning history and any conditions before deciding whether the proposal needs an application.
Planning permission and Building Regulations are separate processes. Depending on the exact property and scope, other matters such as listed building consent, freeholder approval or party-wall procedures may also need to be checked independently.
When planning permission is required
Pre-application advice may be useful for a proposal with unresolved policy or design questions. Check the responsible authority's current service, scope and published charges before deciding whether it is proportionate for the individual project.
A conservation designation does not answer every consent question by itself. Compare the proposed work with the current official guidance and property record, and obtain address-specific advice where the effect of the work is unclear.
Conservation area rules for extensions
An Article 4 direction can withdraw specified Permitted Development rights within its defined boundary. Verify the current direction, map, property inclusion and relevant class for the exact address rather than assuming that every property in an area is affected.
Check the exact address against the responsible authority's current conservation-area map and supporting guidance. A nearby designation or shared postcode does not establish the status of the individual property or the consent route for the proposed work.
Design principles for successful extensions
The practical test for design principles for successful extensions is whether it reduces uncertainty before work begins. Good preparation creates a written scope, identifies the approvals or evidence to verify, and makes clear who is responsible for each step before walls, floors or shared services are opened up.
For this guide topic, the design principles for successful extensions stage should be judged against the property itself rather than a generic national checklist. In NW London, construction, access, leasehold terms, verified designations and previous work can change the appropriate route. Confirm those points before quotes are compared or materials are ordered.
Pre-application advice
The practical test for pre-application advice is whether it reduces uncertainty before work begins. Good preparation creates a written scope, identifies the approvals or evidence to verify, and makes clear who is responsible for each step before walls, floors or shared services are opened up.
For this guide topic, the pre-application advice stage should be judged against the property itself rather than a generic national checklist. In NW London, construction, access, leasehold terms, verified designations and previous work can change the appropriate route. Confirm those points before quotes are compared or materials are ordered.
How to choose an architect for an extension
A reference is more useful when the earlier work is genuinely comparable in building type, scope and constraints. Verify the reference directly and ask what changed during the job; a review or locality label alone does not establish suitability.
Start vetting with the proposed scope. Identify any legal registration or authorisation that applies to that work, verify it on the relevant official register, request current insurance evidence with limits suited to the project, and compare references, contract terms and payment milestones.
Building Regulations for extensions
For this guide topic, the building regulations for extensions stage should be judged against the property itself rather than a generic national checklist. In NW London, construction, access, leasehold terms, verified designations and previous work can change the appropriate route. Confirm those points before quotes are compared or materials are ordered.
When reviewing building regulations for extensions, ask for advice that is specific to the building and exact address. A useful proposal explains what has been inspected, what remains an assumption, and which parts of the work could affect cost, programme or compliance. That clarity is important for house extension and architect in any period home.
Ready to discuss your project?
To arrange a site visit or request a written quote, contact us on +44 20 7101 3168. For regulated work, ask which authorisations and supporting evidence apply to the proposed scope and how they will be checked before acceptance.