House Extension Drawings in Westminster

Which postcode districts around Westminster do we cover for house extension work?

Every Westminster postcode district we draw in, the stock that dominates it and the authority that validates a house extension there. Westminster fees below are the statutory England rates for 2026, not house extension estimates.

How does a house extension differ street by street across Westminster?

Roof pitch, wall build-up and plot depth change every few Westminster streets, and each one changes what a house extension can achieve at that address.

• St John's Wood (NW8) — Victorian villas, mansion blocks defines St John's Wood, where victorian villas, mansion blocks set what a house extension can do. The side-return infill is the classic move on these Victorian terraces — 3 m of permitted development depth plus the width of the original side passage across NW8. Any St John's Wood house extension is validated by Westminster City Council, with Lord's Cricket Ground the usual St John's Wood reference point on the site plan.
• Bayswater (W2) — a house extension in Bayswater starts from victorian stucco terraces, and Bayswater reads as Victorian stucco terraces. The side-return infill is the classic move on these Victorian terraces — 3 m of permitted development depth plus the width of the original side passage in W2. Westminster City Council assesses Bayswater house extensions against its own Bayswater character guidance, and the location plan we draw for Bayswater references Hyde Park.
• Paddington (W2) — Regency and Victorian terraces, canal-side regen defines Paddington, where regency terraces, modern apartments set what a house extension can do. Modern housing here is frequently covered by a planning condition removing permitted development rights across W2. Any Paddington house extension is validated by Westminster City Council, with Paddington Basin the usual Paddington reference point on the site plan.
• Victoria (SW1E, SW1W) — house extension work in Victoria means regency terraces, post-war flats. Victoria is Regency terraces, mixed-use. Post-war houses on these estates often sit under an estate management scheme throughout SW1E. Westminster City Council decides the Victoria application, and Victoria Station anchors the Victoria location plan.
• Westbourne Green (W2, W9) — a house extension in Westbourne Green starts from victorian terraces, mansion blocks, and Westbourne Green reads as Victorian terraces and mansion blocks. The side-return infill is the classic move on these Victorian terraces — 3 m of permitted development depth plus the width of the original side passage in W2. Westminster City Council assesses Westbourne Green house extensions against its own Westbourne Green character guidance, and the location plan we draw for Westbourne Green references Royal Oak.
• Maida Vale (W9) — house extension work in Maida Vale means edwardian mansion blocks, victorian villas. Maida Vale is Edwardian mansion blocks, canal-side. The side-return infill is the classic move on these Victorian terraces — 3 m of permitted development depth plus the width of the original side passage throughout W9. Westminster City Council decides the Maida Vale application, and Little Venice anchors the Maida Vale location plan.
• Mayfair (W1J, W1K) — a house extension in Mayfair starts from georgian townhouses, listed buildings, and Mayfair reads as Georgian listed townhouses, luxury. Georgian rear elevations here are usually the listed or locally listed face of the building in W1J. Westminster City Council assesses Mayfair house extensions against its own Mayfair character guidance, and the location plan we draw for Mayfair references Berkeley Square.

What local planning policy applies to a house extension in Westminster?

Westminster conservation designations: there are 56 across Westminster City Council, Mayfair, Belgravia, Marylebone among them. Designation costs a Westminster owner the permitted-development route: a house extension then needs a £548 householder application over 8 weeks, in place of the £249 prior approval route that takes 6 weeks. Belgravia is the Westminster designation that most often changes a house extension design.

What Article 4 removes near Westminster: Multiple Article 4 Directions — office-to-residential restrictions, HMO conversions, retail to residential in shopping zones. Before pricing a house extension we check whether the NW8 address is inside the mapped area, because Westminster City Council draws the Westminster boundary street by street rather than across the whole of Westminster.

Digging below a Westminster property: Westminster basement policy restricts to single-storey, typically under 50% of rear garden footprint; lightwells and rooflights strictly controlled in conservation areas. Where a house extension in Westminster involves excavation that is read beside the Party Wall etc. Act 1996, which needs two months notice for a Westminster dig within 3 m of a neighbour, and Westminster City Council expects the NW8 ground conditions addressed in the application.

Westminster housing stock: Grand Georgian and Regency terraces in Belgravia and Pimlico; Victorian and Edwardian mansion blocks; heritage-rich townhouses throughout; very high listed building density. Heritage-first planning approach; listed buildings on almost every street; basement and rear extension policies particularly strict. Read that before choosing a house extension route in Westminster — construction, not postcode, sets what is achievable. Westminster City Council charges £548 for a householder application and has 8 weeks to determine it.

Who decides a house extension on the edge of Westminster?

• Lambeth — the Lambeth boundary runs against Westminster, so a house extension a street from Westminster is decided by Lambeth Council instead. Lambeth runs 64 conservation areas across SE1 and its neighbours, which is why house extensions priced for Westminster are re-checked against Lambeth policy whenever the Westminster address sits on that edge.
• City of London — adjoining Westminster, with 27 conservation areas centred on EC1. A house extension on the far side of the Westminster line is determined by City of London Corporation, so the Westminster quote for house extensions is checked against City of London guidance before it is issued.
• Camden — the Camden boundary runs against Westminster, so a house extension a street from Westminster is decided by Camden Council instead. Camden runs 40 conservation areas across NW1 and its neighbours, which is why house extensions priced for Westminster are re-checked against Camden policy whenever the Westminster address sits on that edge.
• Kensington and Chelsea — cross the Westminster boundary and RBKC Planning takes the house extension instead, applying 38 conservation areas of its own around SW1. We re-price house extensions at the Westminster edge because Kensington and Chelsea policy and Westminster policy rarely align on house extension depth.

Sources for this Westminster house extension page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.