Mansard Roof Extensions in Wandsworth

Which Wandsworth postcodes does this mansard roof extension service cover?

Every Wandsworth postcode district we draw in, the stock that dominates it and the authority that validates a mansard roof extension there. Wandsworth 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 Wandsworth?

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

• Wandsworth Common (SW17, SW18) — mansard roof extension work in Wandsworth Common means victorian villas and terraces. Wandsworth Common is Victorian villas around the common. A mansard on a Victorian terrace almost always needs full planning permission throughout SW17. Wandsworth Council decides the Wandsworth Common application, and Wandsworth Common anchors the Wandsworth Common location plan.
• Earlsfield (SW18) — Victorian terraced streets defines Earlsfield, where victorian terraces set what a mansard roof extension can do. A mansard on a Victorian terrace almost always needs full planning permission across SW18. Any Earlsfield mansard roof extension is validated by Wandsworth Council, with Earlsfield station the usual Earlsfield reference point on the site plan.
• Putney (SW15) — mansard roof extension work in Putney means edwardian terraces, victorian villas, mansion blocks. Putney is Edwardian terraces, riverside. A mansard on a Victorian terrace almost always needs full planning permission throughout SW15. Wandsworth Council decides the Putney application, and Putney Bridge anchors the Putney location plan.
• Southfields (SW18) — a mansard roof extension in Southfields starts from 1930s semi-detached, edwardian terraces, and Southfields reads as 1930s semi-detached, grid plan. Edwardian parapets give a mansard a clean base line in SW18. Wandsworth Council assesses Southfields mansard roof extensions against its own Southfields character guidance, and the location plan we draw for Southfields references Southfields station.
• Tonsleys (SW18) — Victorian conservation area defines Tonsleys, where victorian terraces set what a mansard roof extension can do. A mansard on a Victorian terrace almost always needs full planning permission across SW18. Any Tonsleys mansard roof extension is validated by Wandsworth Council, with Tonsley Hill the usual Tonsleys reference point on the site plan.
• Nightingale Triangle (SW12) — a mansard roof extension in Nightingale Triangle starts from edwardian terraces and villas, and Nightingale Triangle reads as Edwardian conservation area. Edwardian parapets give a mansard a clean base line in SW12. Wandsworth Council assesses Nightingale Triangle mansard roof extensions against its own Nightingale Triangle character guidance, and the location plan we draw for Nightingale Triangle references Nightingale Lane.
• Roehampton (SW15) — a mansard roof extension in Roehampton starts from post-war estates, georgian villas, and Roehampton reads as Modernist post-war estates, Georgian fragments. Mansards read as original on Georgian terraces in SW15. Wandsworth Council assesses Roehampton mansard roof extensions against its own Roehampton character guidance, and the location plan we draw for Roehampton references Alton Estate.

What local planning policy applies to a mansard roof extension in Wandsworth?

How designation changes a Wandsworth mansard roof extension: Wandsworth Council maintains 45 conservation areas, including Nightingale Triangle, Wandsworth Common, Clapham Common West. Inside any of them a Wandsworth mansard roof extension cannot rely on permitted development, and the route becomes a £548 householder application determined in 8 weeks rather than a £249 prior approval in 6 weeks. Nightingale Triangle sets the tone for Wandsworth casework.

Wandsworth and Article 4: Article 4 for HMO conversions covering the whole borough. A mansard roof extension planned at a SW11 address is checked against that direction first; Wandsworth Council publishes the Wandsworth extent, and the SW11 line rarely follows the Wandsworth boundary you would expect.

Wandsworth housing stock: Extensive Victorian terraced streets — the classic London side-return extension opportunity; Edwardian villas around the commons; 1930s semi-detached in Southfields. Family-oriented, high side-return extension and loft conversion rates; planning department experienced with Victorian terrace modifications. Read that before choosing a mansard roof extension route in Wandsworth — construction, not postcode, sets what is achievable. Wandsworth Council charges £548 for a householder application and has 8 weeks to determine it.

Who decides a mansard roof extension on the edge of Wandsworth?

• Westminster — adjoining Wandsworth, with 56 conservation areas centred on SW1. A mansard roof extension on the far side of the Wandsworth line is determined by Westminster City Council, so the Wandsworth quote for mansard roof extensions is checked against Westminster guidance before it is issued.
• Lambeth — adjoining Wandsworth, with 64 conservation areas centred on SE1. A mansard roof extension on the far side of the Wandsworth line is determined by Lambeth Council, so the Wandsworth quote for mansard roof extensions is checked against Lambeth guidance before it is issued.
• Merton — cross the Wandsworth boundary and Merton Council takes the mansard roof extension instead, applying 28 conservation areas of its own around SW16. We re-price mansard roof extensions at the Wandsworth edge because Merton policy and Wandsworth policy rarely align on mansard roof extension depth.
• Kingston upon Thames — the Kingston upon Thames boundary runs against Wandsworth, so a mansard roof extension a street from Wandsworth 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 Wandsworth are re-checked against Kingston upon Thames policy whenever the Wandsworth address sits on that edge.

Sources for this Wandsworth 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.