What you could build at BR4 9PF: 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 West Wickham, Bromley.
61extensions seen within 600 m in the last 10 years
6loft conversions within 600 m in the last 10 years
81.1extensions 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.
Not in a conservation area (from council registers).
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 West Wickham.
Move to a home 20 m² bigger (about £830,000)
Stamp duty on the new home
£31,500
Estate agent on yours 1.2% + VAT
£10,224
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£46,824
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
−£72,000
Money gone
−£14,500
On these figures, extending loses about £61,324 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.
7, Oak Avenue, Cr0 8en
Rear extension
Approved
Jun 2025
25/00997/HSE
33, Cavendish Way, Br4 0lg
Rear extension
Approved
Jun 2025
25/01065/FULL6
22, Wilmar Gardens, Br4 0lh
Side return or wrap-around
Approved
May 2025
25/00983/FULL6
11, Cavendish Way, Br4 0lg
Rear extension
Not needed / lawful
May 2025
25/01315/HHPA
44, Copse Avenue, Br4 9nr
Loft or dormer
Refused
May 2025
25/00760/FULL6
17, Bramley Way, Br4 9nt
Rear extension
Approved
May 2025
25/00892/FULL6
6, Cunningham Close, Br4 9pj
Side return or wrap-around
Approved
May 2025
25/00714/FULL6
47, Oak Avenue, Cr0 8ep
Loft or dormer
Approved
Apr 2025
25/00616/HSE
53, Manor Park Road, Br4 0jy
Side return or wrap-around
Approved
Apr 2025
25/00449/FULL6
86, The Grove, Br4 9jt
Loft or dormer
Approved
Feb 2025
24/04573/FULL6
105, Oak Avenue, Cr0 8eq
Rear extension
Approved
Feb 2025
24/04291/HSE
31, Links View Road, Cr0 8nb
Outbuilding or garden room
Approved
Jan 2025
24/04128/HSE
7, Copse Avenue, Br4 9nl
Two-storey extension
Approved
Jan 2025
24/04243/FULL6
1, Woodland Way, Br4 9ll
Garage conversion or garage
Approved
Dec 2024
24/04093/FULL6
16, Copse Avenue, Br4 9nl
Side return or wrap-around
Approved
Dec 2024
24/03904/FULL6
37, Bridle Road, Cr0 8hn
Other householder work
Approved
Dec 2024
24/03471/HSE
40, Woodland Way, Br4 9lr
Loft or dormer
Approved
Nov 2024
24/03601/FULL6
10, Springfield Gardens, Br4 9px
Garage conversion or garage
Approved
Nov 2024
24/03441/FULL6
37, Ravenswood Avenue, Br4 0pn
Rear extension
Approved
Oct 2024
24/03386/FULL6
70, Hawkhurst Way, Br4 9pf
Two-storey extension
Approved
Oct 2024
24/02866/FULL6
17, Bolderwood Way, Br4 9ph
Two-storey extension
Approved
Nov 2024
24/02928/FULL6
9, Park Avenue, Br4 9ju
Loft or dormer
Approved
Sept 2024
24/02864/FULL6
8, Woodland Way, Br4 9ll
Side return or wrap-around
Approved
Sept 2024
24/02781/FULL6
70, Oak Avenue, Cr0 8eg
Rear extension
Approved
Aug 2024
24/02074/HSE
46, Boleyn Gardens, Br4 9nq
Rear extension
Approved
Aug 2024
24/02194/FULL6
18, Hawkhurst Way, Br4 9pf
Rear extension
Approved
Aug 2024
24/02322/FULL6
2, Arragon Gardens, Br4 9lj
Loft or dormer
Approved
Jul 2024
24/02210/FULL6
23, Hawkhurst Way, Br4 9pe
Rear extension
Approved
Jul 2024
24/01878/FULL6
43, Hawkhurst Way, Br4 9pe
Rear extension
Not needed / lawful
Jun 2024
24/01745/HHPA
9, Braemar Gardens, Br4 0jn
Loft or dormer
Approved
Jul 2024
24/01523/FULL6
8, Bolderwood Way, Br4 9ph
Rear extension
Approved
Jun 2024
24/01541/FULL6
16, Chessington Way, Br4 9nz
Rear extension
Not needed / lawful
May 2024
24/01342/HHPA
45, Pine Avenue, Br4 0ln
Outbuilding or garden room
Approved
May 2024
24/01185/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.
88% (8)
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.