Wimbledon Village basements: Merton decides 99.3% itself

Which postcode districts around Merton do we cover for basement extension work?

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

What changes about a basement extension in each part of Merton?

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

• Wimbledon (SW19, SW20) — Victorian villas, Edwardian terraces defines Wimbledon, where victorian villas, edwardian terraces set what a basement extension can do. Victorian cellars here convert without planning permission when the footprint and external appearance are unchanged across SW19. Any Wimbledon basement extension is validated by Merton Council, with All England Club the usual Wimbledon reference point on the site plan.
• Wimbledon Village (SW19) — Georgian and Victorian village conservation defines Wimbledon Village, where georgian and victorian villas set what a basement extension can do. Georgian houses here already have a vault and a lower-ground floor across SW19. Any Wimbledon Village basement extension is validated by Merton Council, with Wimbledon Village High Street the usual Wimbledon Village reference point on the site plan.
• Raynes Park (SW20) — 1930s semi-detached, Edwardian terraces defines Raynes Park, where 1930s semi-detached, edwardian terraces set what a basement extension can do. Edwardian houses rarely have a usable cellar across SW20. Any Raynes Park basement extension is validated by Merton Council, with Raynes Park station the usual Raynes Park reference point on the site plan.
• Morden (SM4) — a basement extension in Morden starts from 1930s semi-detached, post-war flats, and Morden reads as 1930s semi-detached, post-war flats. 1930s houses were built without cellars in SM4. Merton Council assesses Morden basement extensions against its own Morden character guidance, and the location plan we draw for Morden references Morden Tube.
• Mitcham (CR4) — 1930s semi-detached, post-war estates defines Mitcham, where 1930s semi-detached, post-war estates set what a basement extension can do. 1930s houses were built without cellars across CR4. Any Mitcham basement extension is validated by Merton Council, with Mitcham Cricket Green the usual Mitcham reference point on the site plan.
• Colliers Wood (SW19) — a basement extension in Colliers Wood starts from edwardian terraces, post-war flats, and Colliers Wood reads as Edwardian terraces, post-war flats. Edwardian houses rarely have a usable cellar in SW19. Merton Council assesses Colliers Wood basement extensions against its own Colliers Wood character guidance, and the location plan we draw for Colliers Wood references Colliers Wood Tube.
• South Wimbledon (SW19) — Edwardian terraces defines South Wimbledon, where edwardian terraces set what a basement extension can do. Edwardian houses rarely have a usable cellar across SW19. Any South Wimbledon basement extension is validated by Merton Council, with South Wimbledon Tube the usual South Wimbledon reference point on the site plan.

Does Merton planning policy restrict a basement extension?

Merton conservation designations: there are 28 across Merton Council, Wimbledon Village, John Innes, Mitcham Cricket Green among them. Designation costs a Merton owner the permitted-development route: a basement extension then needs a £548 householder application over 8 weeks, in place of the £249 prior approval route that takes 6 weeks. Wimbledon Village is the Merton designation that most often changes a basement extension design.

Merton permitted development status: there is no borough-wide direction from Merton Council, so a basement extension at a SW19 address is normally still permitted development. We certify that with a £274 Lawful Development Certificate rather than leaving a Merton sale to argue it later.

The building fabric around Merton: Victorian villas in Wimbledon; Edwardian terraces in Tooting and Colliers Wood; 1930s semi-detached in Morden and Raynes Park; post-war flats in Mitcham. Wimbledon is heavily conservation-controlled; outer Merton (Morden, Mitcham) is permissive. A basement extension in Merton is scoped against that stock first.

What happens if a Merton property sits on a boundary?

• Sutton — adjoining Merton, with 17 conservation areas centred on SM1. A basement extension on the far side of the Merton line is determined by Sutton Council, so the Merton quote for basement extensions is checked against Sutton guidance before it is issued.
• Kingston upon Thames — the Kingston upon Thames boundary runs against Merton, so a basement extension a street from Merton is decided by Kingston Council instead. Kingston upon Thames runs 22 conservation areas across KT1 and its neighbours, which is why basement extensions priced for Merton are re-checked against Kingston upon Thames policy whenever the Merton address sits on that edge.
• Wandsworth — cross the Merton boundary and Wandsworth Council takes the basement extension instead, applying 45 conservation areas of its own around SW8. We re-price basement extensions at the Merton edge because Wandsworth policy and Merton policy rarely align on basement extension depth.
• Lambeth — the Lambeth boundary runs against Merton, so a basement extension a street from Merton is decided by Lambeth Council instead. Lambeth runs 64 conservation areas across SE1 and its neighbours, which is why basement extensions priced for Merton are re-checked against Lambeth policy whenever the Merton address sits on that edge.

Sources for this Merton basement 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.