Which postcode districts around Blackheath (Greenwich) do we cover for mansard roof extension work?
Every Blackheath (Greenwich) postcode district we draw in, the stock that dominates
it and the authority that validates a mansard roof extension there. Blackheath (Greenwich) 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 |
|---|
| SE3 | Blackheath / Kidbrooke | Georgian villas, Victorian terraces | Blackheath / Kidbrooke is split at SE3. Either Greenwich Council or Lewisham Council can determine a mansard roof extension here, so the SE3 address is checked against both policies maps first. |
| SE10 | Greenwich | Georgian terraces, listed buildings | Neighbouring Greenwich, where mansard roof extension work is handled by the same Greenwich Council case officers. |
| SE7 | Charlton | Victorian villas, 1930s semi-detached | Neighbouring Charlton, where mansard roof extension work is handled by the same Greenwich Council case officers. |
| SE18 | Woolwich | Georgian fragments, post-war estates, new-build | Neighbouring Woolwich, where mansard roof extension work is handled by the same Greenwich Council case officers. |
| SE9 | Eltham | 1930s semi-detached, post-war flats | Neighbouring Eltham, where mansard roof extension work is handled by the same Greenwich Council case officers. |
| SE28 | Thamesmead | Post-war estates, new-build | Neighbouring Thamesmead, where mansard roof extension work is handled by the same Greenwich Council case officers. |
| SE3 | Kidbrooke | New-build, post-war fragments | Neighbouring Kidbrooke, where mansard roof extension work is handled by the same Greenwich Council case officers. |
| SE9 | New Eltham | 1930s semi-detached | Neighbouring New Eltham, where mansard roof extension work is handled by the same Greenwich Council case officers. |
Which Blackheath (Greenwich) neighbourhoods suit a mansard roof extension best?
Roof pitch, wall build-up and plot depth change every few Blackheath (Greenwich)
streets, and each one changes what a mansard roof extension can achieve at that address.
- Blackheath (Greenwich) (SE3) — mansard roof extension work in Blackheath (Greenwich) means georgian villas, victorian terraces. Blackheath (Greenwich) is Georgian villas around the heath. Mansards read as original on Georgian terraces throughout SE3. Greenwich Council decides the Blackheath (Greenwich) application, and Blackheath Common anchors the Blackheath (Greenwich) location plan.
- Near Blackheath (Greenwich): Kidbrooke (SE3) — regenerated quarter, new-build estate defines Kidbrooke, where new-build, post-war fragments set what a mansard roof extension can do. Mansards on post-war blocks are a structural and fire-strategy exercise before they are an aesthetic one across SE3. Any Kidbrooke mansard roof extension is validated by Greenwich Council, with Kidbrooke Village the usual Kidbrooke reference point on the site plan.
- Near Blackheath (Greenwich): New Eltham (SE9) — a mansard roof extension in New Eltham starts from 1930s semi-detached, and New Eltham reads as 1930s semi-detached. Mansards are rare on 1930s stock — the hipped roof form works against the geometry in SE9. Greenwich Council assesses New Eltham mansard roof extensions against its own New Eltham character guidance, and the location plan we draw for New Eltham references New Eltham station.
- Near Blackheath (Greenwich): Greenwich (SE10) — Georgian World Heritage centre defines Greenwich, where georgian terraces, listed buildings set what a mansard roof extension can do. Mansards read as original on Georgian terraces across SE10. Any Greenwich mansard roof extension is validated by Greenwich Council, with Royal Observatory the usual Greenwich reference point on the site plan.
- Near Blackheath (Greenwich): Charlton (SE7) — mansard roof extension work in Charlton means victorian villas, 1930s semi-detached. Charlton is Victorian villas, 1930s semi-detached. A mansard on a Victorian terrace almost always needs full planning permission throughout SE7. Greenwich Council decides the Charlton application, and Charlton House anchors the Charlton location plan.
- Near Blackheath (Greenwich): Woolwich (SE18) — mansard roof extension work in Woolwich means georgian fragments, post-war estates, new-build. Woolwich is Georgian arsenal heritage, riverside regen. Mansards read as original on Georgian terraces throughout SE18. Greenwich Council decides the Woolwich application, and Royal Arsenal anchors the Woolwich location plan.
- Near Blackheath (Greenwich): Eltham (SE9) — a mansard roof extension in Eltham starts from 1930s semi-detached, post-war flats, and Eltham reads as 1930s semi-detached, Tudor fragments. Mansards are rare on 1930s stock — the hipped roof form works against the geometry in SE9. Greenwich Council assesses Eltham mansard roof extensions against its own Eltham character guidance, and the location plan we draw for Eltham references Eltham Palace.
Does Blackheath (Greenwich) planning policy restrict a mansard roof extension?
Conservation areas covering Blackheath (Greenwich): Greenwich Council runs 20, and Eltham Park, Greenwich Town Centre (World Heritage Site), Blackheath are the ones Blackheath (Greenwich) owners meet most. A mansard roof extension inside a Blackheath (Greenwich) conservation area loses permitted development, so the Blackheath (Greenwich) submission is a householder application at £548 decided in 8 weeks — not a £249 prior approval decided in 6 weeks. In Charlton a mansard roof extension is judged on the street elevation first.
Article 4 and your Blackheath (Greenwich) mansard roof extension: Greenwich Council has made no borough-wide direction, so permitted development for a mansard roof extension in Blackheath (Greenwich) generally survives outside Blackheath (Greenwich) conservation areas and listed curtilages. A Lawful Development Certificate at £274 is how a SE3 owner records that a mansard roof extension was lawful.
What Blackheath (Greenwich) is built from: Georgian in Greenwich town centre; Victorian terraces in East Greenwich, Charlton; inter-war semi-detached in Eltham; new-build along the riverside. World Heritage Site status in Greenwich town centre adds heritage weight; outer borough areas (Eltham, Thamesmead) generally permissive. That mix decides the mansard roof extension route in Blackheath (Greenwich) more than the postcode does, and it is what a Greenwich Council case officer reads first. A householder application costs £548 paid to Greenwich Council direct, with 8 weeks to a decision once validated.
Which neighbouring authorities border Blackheath (Greenwich)?
- Bromley — adjoining Blackheath (Greenwich), with 48 conservation areas centred on BR1. A mansard roof extension on the far side of the Blackheath (Greenwich) line is determined by Bromley Council, so the Blackheath (Greenwich) quote for mansard roof extensions is checked against Bromley guidance before it is issued.
- Newham — adjoining Blackheath (Greenwich), with 10 conservation areas centred on E6. A mansard roof extension on the far side of the Blackheath (Greenwich) line is determined by Newham Council, so the Blackheath (Greenwich) quote for mansard roof extensions is checked against Newham guidance before it is issued.
- Tower Hamlets — the Tower Hamlets boundary runs against Greenwich, so a mansard roof extension a street from Blackheath (Greenwich) is decided by Tower Hamlets Council instead. Tower Hamlets runs 58 conservation areas across E1 and its neighbours, which is why mansard roof extensions priced for Blackheath (Greenwich) are re-checked against Tower Hamlets policy whenever the Blackheath (Greenwich) address sits on that edge.
- Lewisham — adjoining Blackheath (Greenwich), with 30 conservation areas centred on SE3. A mansard roof extension on the far side of the Blackheath (Greenwich) line is determined by Lewisham Council, so the Blackheath (Greenwich) quote for mansard roof extensions is checked against Lewisham guidance before it is issued.
Sources for this Blackheath (Greenwich) 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.
