Mansard Roof Extensions in Merton

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

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

What changes about a mansard roof 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 mansard roof extension can achieve at that address.

• Wimbledon (SW19, SW20) — mansard roof extension work in Wimbledon means victorian villas, edwardian terraces. Wimbledon is Victorian villas, Edwardian terraces. A mansard on a Victorian terrace almost always needs full planning permission throughout SW19. Merton Council decides the Wimbledon application, and All England Club anchors the Wimbledon location plan.
• Wimbledon Village (SW19) — mansard roof extension work in Wimbledon Village means georgian and victorian villas. Wimbledon Village is Georgian and Victorian village conservation. Mansards read as original on Georgian terraces throughout SW19. Merton Council decides the Wimbledon Village application, and Wimbledon Village High Street anchors the Wimbledon Village location plan.
• Raynes Park (SW20) — mansard roof extension work in Raynes Park means 1930s semi-detached, edwardian terraces. Raynes Park is 1930s semi-detached, Edwardian terraces. Edwardian parapets give a mansard a clean base line throughout SW20. Merton Council decides the Raynes Park application, and Raynes Park station anchors the Raynes Park location plan.
• Morden (SM4) — a mansard roof extension in Morden starts from 1930s semi-detached, post-war flats, and Morden reads as 1930s semi-detached, post-war flats. Mansards are rare on 1930s stock — the hipped roof form works against the geometry in SM4. Merton Council assesses Morden mansard roof 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 mansard roof extension can do. Mansards are rare on 1930s stock — the hipped roof form works against the geometry across CR4. Any Mitcham mansard roof extension is validated by Merton Council, with Mitcham Cricket Green the usual Mitcham reference point on the site plan.
• Colliers Wood (SW19) — a mansard roof extension in Colliers Wood starts from edwardian terraces, post-war flats, and Colliers Wood reads as Edwardian terraces, post-war flats. Edwardian parapets give a mansard a clean base line in SW19. Merton Council assesses Colliers Wood mansard roof extensions against its own Colliers Wood character guidance, and the location plan we draw for Colliers Wood references Colliers Wood Tube.
• South Wimbledon (SW19) — mansard roof extension work in South Wimbledon means edwardian terraces. South Wimbledon is Edwardian terraces. Edwardian parapets give a mansard a clean base line throughout SW19. Merton Council decides the South Wimbledon application, and South Wimbledon Tube anchors the South Wimbledon location plan.

How do conservation areas and Article 4 affect a mansard roof extension in Merton?

Conservation areas covering Merton: Merton Council runs 28, and Mitcham Cricket Green, Wimbledon Common, Wimbledon Village are the ones Merton owners meet most. A mansard roof extension 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 mansard roof extension is judged on the street elevation first.

Article 4 and your Merton mansard roof extension: Merton Council has made no borough-wide direction, so permitted development for a mansard roof extension 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 mansard roof extension was lawful.

Merton housing stock: 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. Read that before choosing a mansard roof extension route in Merton — construction, not postcode, sets what is achievable. Merton Council charges £548 for a householder application and has 8 weeks to determine it.

Which neighbouring authorities border Merton?

• Kingston upon Thames — the Kingston upon Thames boundary runs against Merton, so a mansard roof 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 mansard roof extensions priced for Merton are re-checked against Kingston upon Thames policy whenever the Merton address sits on that edge.
• Wandsworth — the Wandsworth boundary runs against Merton, so a mansard roof extension a street from Merton is decided by Wandsworth Council instead. Wandsworth runs 45 conservation areas across SW8 and its neighbours, which is why mansard roof extensions priced for Merton are re-checked against Wandsworth policy whenever the Merton address sits on that edge.
• Lambeth — cross the Merton boundary and Lambeth Council takes the mansard roof extension instead, applying 64 conservation areas of its own around SE1. We re-price mansard roof extensions at the Merton edge because Lambeth policy and Merton policy rarely align on mansard roof extension depth.
• Croydon — cross the Merton boundary and Croydon Council takes the mansard roof extension instead, applying 24 conservation areas of its own around CR0. We re-price mansard roof extensions at the Merton edge because Croydon policy and Merton policy rarely align on mansard roof extension depth.

Sources for this Merton mansard roof 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.