Basement Conversion Drawings in Merton

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

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

What changes about a basement conversion 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 conversion can achieve at that address.

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

What local planning policy applies to a basement conversion in Merton?

Conservation areas covering Merton: Merton Council runs 28, and John Innes, Mitcham Cricket Green, Wimbledon Common are the ones Merton owners meet most. A basement conversion inside a Merton conservation area loses permitted development, so the Merton submission is a householder application at £548 decided in 8 weeks — not a £249 prior approval decided in 6 weeks. In Wimbledon Village a basement conversion is judged on the street elevation first.

Article 4 and your Merton basement conversion: Merton Council has made no borough-wide direction, so permitted development for a basement conversion in Merton generally survives outside Merton conservation areas and listed curtilages. A Lawful Development Certificate at £274 is how a SW19 owner records that a basement conversion was lawful.

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 conversion in Merton is scoped against that stock first, because it decides whether the scheme runs as permitted development, a £274 Lawful Development Certificate, or a full £548 application to Merton Council.

What happens if a Merton property sits on a boundary?

• Wandsworth — the Wandsworth boundary runs against Merton, so a basement conversion a street from Merton is decided by Wandsworth Council instead. Wandsworth runs 45 conservation areas across SW8 and its neighbours, which is why basement conversions priced for Merton are re-checked against Wandsworth policy whenever the Merton address sits on that edge.
• Lambeth — adjoining Merton, with 64 conservation areas centred on SE1. A basement conversion on the far side of the Merton line is determined by Lambeth Council, so the Merton quote for basement conversions is checked against Lambeth guidance before it is issued.
• Croydon — adjoining Merton, with 24 conservation areas centred on CR0. A basement conversion on the far side of the Merton line is determined by Croydon Council, so the Merton quote for basement conversions is checked against Croydon guidance before it is issued.
• Sutton — adjoining Merton, with 17 conservation areas centred on SM1. A basement conversion on the far side of the Merton line is determined by Sutton Council, so the Merton quote for basement conversions is checked against Sutton guidance before it is issued.

Sources for this Merton basement conversion 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.