What you could build at BR7 5EY: the planning rules at this address, what neighbours have built and how big, planning decisions nearby, rough costs and the value an extension adds, and how to get started. In Chislehurst West & Elmstead, Bromley.
28extensions seen within 600 m in the last 10 years
1loft conversions within 600 m in the last 10 years
129.1extensions per 1,000 homes in the neighbourhood (10 years)
● work seen on energy certificates · ● application approved · ● refused · ● pending or other · ● this postcode
The rules at this address
Houses usually have permitted development rights: some rear extensions (typically up to 3 m deep for a semi or terrace, 4 m detached), loft conversions within volume limits, and porches can go ahead without planning permission. Larger single-storey rear extensions (up to 6 m / 8 m) can use the “prior approval” neighbour scheme.
In the Chislehurst conservation area: permitted development is narrower (for example no side extensions or roof cladding), and demolition and works to trees need consent.
No Article 4 direction recorded for this postcode.
Listed buildings need listed building consent for most changes, inside and out: check the National Heritage List.
To be certain work is permitted development, apply for a lawful development certificate (about £129 for householders in England). Building regulations apply either way.
Across England and Wales, homes extended by a typical 30 m² and then resold rose about 11.1% more than similar homes nearby over the same years (124,884 resales). How extensions pay off by size, type and region.
Single-storey rear or side extension: about £2,000–£3,000 per m² (London £2,500–£4,000), plus fees and VAT
Loft conversion: about £45,000–£75,000 for a dormer; more for a mansard or hip-to-gable
Two-storey extension: about £1,800–£2,800 per m² of new floor
Garage conversion: about £15,000–£30,000
Basement: about £3,500–£5,000 per m², London mostly
Build costs are rough 2026 ranges from industry guides, not quotes. Get three quotes for your plans.
Move or improve?
The money you don't get back either way, for the same extra space in Chislehurst West & Elmstead.
Move to a home 20 m² bigger (about £910,000)
Stamp duty on the new home
£35,500
Estate agent on yours 1.2% + VAT
£11,304
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£51,904
Extend by 20 m²
Building, plus 15% for design, planning and contingency
£57,500
Less what it adds to your home's value 60% of the local price
−£75,000
Money gone
−£17,500
On these figures, extending loses about £69,404 less. Moving also changes the area, the schools and the commute; extending means months of building work and depends on planning.
Building costs vary a lot (a single-storey rear extension is often £2,000–£3,000 per m², more in London). How much space adds depends on the home and street: what extensions added to resale prices. A guide, not advice; nothing you type leaves this page.
Getting started
Look at what neighbours did. Open applications above to see drawings that were approved on similar houses, and who designed them.
Check the route: permitted development (with a lawful development certificate), prior approval for larger rear extensions, or full householder planning permission.
Get a measured survey and a designer: an architect, an architectural technologist or a designer who handles planning drawings.
Apply (householder permission is about £258 in England; councils aim to decide within 8 weeks).
Building regulations through the council's building control or an approved inspector, and party wall notices to neighbours if you build on or near the boundary.
Choose a builder: written quotes, a contract, staged payments, and check their insurance and references.
From energy certificates: an extension where a later certificate shows more floor space, a loft conversion where roof rooms appear. Certificates come with sales, lettings and some building work, so the year is when it was first seen.
Not every extension shows here. We only see building work when a new energy certificate is lodged, which happens when a home is sold, let or newly built. A loft or extension added since then won't appear, even with planning permission and building control sign-off, because those records aren't published as open data outside London. Missing work doesn't mean missing paperwork.
24, Ashfield Lane, Br7 6lq
Side extension
Approved
Apr 2025
25/00383/FULL6
The White House, Raggleswood, Br7 5nh
Loft or dormer
Approved
Feb 2025
24/04823/FULL6
Langwell House, Willow Grove, Br7 5bn
Loft or dormer
Approved
Feb 2025
24/04692/FULL6
Dees Holt, Raggleswood, Br7 5nh
Loft or dormer
Approved
Feb 2025
24/04663/FULL6
Sherbrooke, Heathfield Lane, Br7 6ah
Two-storey extension
Approved
Feb 2025
24/03858/FULL6
Haddon, Beechcroft, Br7 5db
Side extension
Approved
Dec 2024
24/03918/FULL6
Langwell House, Willow Grove, Br7 5bn
Loft or dormer
Refused
Dec 2024
24/03815/FULL6
2, Courtlands, Prince Imperial Road, Br7 5lx
Loft or dormer
Approved
Oct 2024
24/03380/FULL6
Lothlorien, Cricket Ground Road, Br7 5hd
Garage conversion or garage
Approved
Sept 2024
24/02799/FULL6
Dees Holt, Raggleswood, Br7 5nh
Loft or dormer
Refused
Nov 2024
24/02140/FULL6
1, Green Lane, Br7 6ag
Windows, doors or cladding
Approved
Jul 2024
24/01700/FULL6
2, Pond Path, Br7 6aj
Loft or dormer
Approved
May 2024
24/01271/FULL6
St Michaels, West Lodge, School Road, Br7 5pq
Windows, doors or cladding
Approved
Apr 2024
24/00523/FULL6
9, The Meadow, Br7 6aa
Loft or dormer
Refused
Jul 2024
24/00562/FULL6
5, Camden Grove, Br7 5bh
Loft or dormer
Approved
Feb 2024
23/04731/FULL6
Wallings, Heathfield Lane, Br7 6ah
Two-storey extension
Withdrawn
May 2024
23/04624/FULL6
14, Trosley, Wilderness Road, Br7 5ey
Basement
Approved
May 2024
23/03915/FULL6
The Crest, Raggleswood, Br7 5nh
Two-storey extension
Approved
Dec 2023
23/03973/FULL6
Dees Holt, Raggleswood, Br7 5nh
Loft or dormer
Refused
Feb 2024
23/03809/FULL6
39, Heathfield, Br7 6af
Loft or dormer
Approved
Dec 2023
23/03458/FULL6
3b, Old Court House, Old Hill, Br7 5lz
Windows, doors or cladding
Approved
Oct 2023
23/02967/FULL6
2, Willow Vale, Br7 5df
Garage conversion or garage
Approved
Aug 2023
23/01983/FULL6
Sherbrooke, Heathfield Lane, Br7 6ah
Loft or dormer
Approved
Jan 2024
23/02143/FULL6
2, Wirral Wood Close, Br7 5bj
Loft or dormer
Approved
Jun 2023
23/01433/FULL6
28, Ashfield Lane, Br7 6lq
Other householder work
Approved
Apr 2023
23/00373/FULL6
15, Camden Grove, Br7 5bh
Loft or dormer
Approved
Apr 2023
23/00454/FULL6
7, Foxhome Close, Br7 5xt
Loft or dormer
Approved
Mar 2023
23/00196/FULL6
Capulet, Raggleswood, Br7 5nh
Rear extension
Approved
Feb 2023
22/05068/FULL6
Householder applications validated since 2023 within 600 m. The council's page has the drawings, the decision notice and who the agent or architect was. Hover a row for the description. Source: GLA Planning London Datahub.
Garage conversion or garage
67% (12)
85% (123)
88%
8 weeks
Basement
–
77% (26)
83%
9 weeks
Porch or front extension
–
92% (94)
81%
8 weeks
Share of decided applications approved since 2023 (number decided in brackets). Withdrawn applications aren't counted; many are withdrawn when refusal looks likely.