Where in Richmond does a mansard roof extension actually get determined?
Every Richmond postcode district we draw in, the stock that dominates
it and the authority that validates a mansard roof extension there. Richmond fees below are the
statutory England rates for 2026, not mansard roof extension estimates.
| Postcode | Area | Dominant stock | What it means for a mansard roof extension |
|---|
| TW9 | Richmond / Kew | Georgian terraces, Victorian villas | Richmond / Kew sits wholly inside TW9, so Richmond Council validates every mansard roof extension submitted from an TW9 address. |
| TW10 | Richmond / Ham | Georgian terraces, Victorian villas | Richmond / Ham sits wholly inside TW10, so Richmond Council validates every mansard roof extension submitted from an TW10 address. |
| TW1 | Twickenham | Georgian fragments, Victorian terraces, Edwardian villas | Neighbouring Twickenham, where mansard roof extension work is handled by the same Richmond Council case officers. |
| TW9 | Kew | Georgian and Edwardian villas | Neighbouring Kew, where mansard roof extension work is handled by the same Richmond Council case officers. |
| SW13 | Barnes | Georgian villas, Edwardian terraces | Neighbouring Barnes, where mansard roof extension work is handled by the same Richmond Council case officers. |
| SW14 | East Sheen | Edwardian villas, 1930s semi-detached | Neighbouring East Sheen, where mansard roof extension work is handled by the same Richmond Council case officers. |
| TW11 | Teddington | Edwardian villas, Victorian terraces | Neighbouring Teddington, where mansard roof extension work is handled by the same Richmond Council case officers. |
| TW12 | Hampton | Georgian villas, Edwardian terraces, 1930s semi-detached | Neighbouring Hampton, where mansard roof extension work is handled by the same Richmond Council case officers. |
| TW2 | Whitton | 1930s semi-detached | Neighbouring Whitton, where mansard roof extension work is handled by the same Richmond Council case officers. |
| TW10 | Ham | Georgian villas, post-war estates | Neighbouring Ham, where mansard roof extension work is handled by the same Richmond Council case officers. |
| SW14 | Mortlake | Victorian and Edwardian terraces | Neighbouring Mortlake, where mansard roof extension work is handled by the same Richmond Council case officers. |
What changes about a mansard roof extension in each part of Richmond?
Roof pitch, wall build-up and plot depth change every few Richmond
streets, and each one changes what a mansard roof extension can achieve at that address.
- Richmond (TW9, TW10) — mansard roof extension work in Richmond means georgian terraces, victorian villas. Richmond is Georgian centre, riverside conservation. Mansards read as original on Georgian terraces throughout TW9. Richmond Council decides the Richmond application, and Richmond Green anchors the Richmond location plan.
- Near Richmond: Barnes (SW13) — mansard roof extension work in Barnes means georgian villas, edwardian terraces. Barnes is Georgian and Edwardian village. Mansards read as original on Georgian terraces throughout SW13. Richmond Council decides the Barnes application, and Barnes Common anchors the Barnes location plan.
- Near Richmond: East Sheen (SW14) — mansard roof extension work in East Sheen means edwardian villas, 1930s semi-detached. East Sheen is Edwardian villas, 1930s semi-detached. Edwardian parapets give a mansard a clean base line throughout SW14. Richmond Council decides the East Sheen application, and Sheen Lane anchors the East Sheen location plan.
- Near Richmond: Teddington (TW11) — mansard roof extension work in Teddington means edwardian villas, victorian terraces. Teddington is Edwardian villas, Victorian terraces. A mansard on a Victorian terrace almost always needs full planning permission throughout TW11. Richmond Council decides the Teddington application, and Teddington Lock anchors the Teddington location plan.
- Near Richmond: Hampton (TW12) — a mansard roof extension in Hampton starts from georgian villas, edwardian terraces, 1930s semi-detached, and Hampton reads as Georgian and Edwardian villages. Mansards read as original on Georgian terraces in TW12. Richmond Council assesses Hampton mansard roof extensions against its own Hampton character guidance, and the location plan we draw for Hampton references Hampton Court Palace.
- Near Richmond: Whitton (TW2) — a mansard roof extension in Whitton starts from 1930s semi-detached, and Whitton reads as 1930s semi-detached. Mansards are rare on 1930s stock — the hipped roof form works against the geometry in TW2. Richmond Council assesses Whitton mansard roof extensions against its own Whitton character guidance, and the location plan we draw for Whitton references Whitton station.
- Near Richmond: Ham (TW10) — mansard roof extension work in Ham means georgian villas, post-war estates. Ham is Georgian common, post-war estate. Mansards read as original on Georgian terraces throughout TW10. Richmond Council decides the Ham application, and Ham Common anchors the Ham location plan.
How do conservation areas and Article 4 affect a mansard roof extension in Richmond?
Conservation areas covering Richmond: Richmond Council runs 72, and Twickenham Riverside, Barnes Village, Ham Common are the ones Richmond owners meet most. A mansard roof extension inside a Richmond conservation area loses permitted development, so the Richmond submission is a householder application at £548 decided in 8 weeks — not a £249 prior approval decided in 6 weeks. In Ham Common a mansard roof extension is judged on the street elevation first.
No blanket Article 4 over Richmond: Richmond Council has not withdrawn permitted development across Richmond, so a mansard roof extension outside a Richmond conservation area usually keeps it. The £274 Lawful Development Certificate is still the document a TW9 owner wants on file.
The building fabric around Richmond: Georgian in Richmond Green and Twickenham; Edwardian villas in Barnes and East Sheen; 1930s semi-detached in Whitton; riverside cottages along the Thames. Highest conservation area coverage in London; Royal Parks and Thames corridor add heritage layers; design quality heavily scrutinised. A mansard roof extension in Richmond 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 Richmond Council.
Who decides a mansard roof extension on the edge of Richmond?
- Hounslow — adjoining Richmond, with 30 conservation areas centred on W3. A mansard roof extension on the far side of the Richmond line is determined by Hounslow Council, so the Richmond quote for mansard roof extensions is checked against Hounslow guidance before it is issued.
- Kingston upon Thames — cross the Richmond boundary and Kingston Council takes the mansard roof extension instead, applying 22 conservation areas of its own around KT1. We re-price mansard roof extensions at the Richmond edge because Kingston upon Thames policy and Richmond upon Thames policy rarely align on mansard roof extension depth.
- Wandsworth — adjoining Richmond, with 45 conservation areas centred on SW8. A mansard roof extension on the far side of the Richmond line is determined by Wandsworth Council, so the Richmond quote for mansard roof extensions is checked against Wandsworth guidance before it is issued.
- Hammersmith and Fulham — cross the Richmond boundary and Hammersmith & Fulham Council takes the mansard roof extension instead, applying 45 conservation areas of its own around W6. We re-price mansard roof extensions at the Richmond edge because Hammersmith and Fulham policy and Richmond upon Thames policy rarely align on mansard roof extension depth.
Sources for this Richmond 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.
