What you could build at BR3 5JS: 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 Beckenham East & Kelsey Park, Bromley.
72extensions seen within 600 m in the last 10 years
10loft conversions within 600 m in the last 10 years
64.1extensions 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 Chancery Lane, Beckenham 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 Beckenham East & Kelsey Park.
Move to a home 20 m² bigger (about £587,000)
Stamp duty on the new home
£19,350
Estate agent on yours 1.2% + VAT
£6,768
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£31,218
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
−£70,200
Money gone
−£12,700
On these figures, extending loses about £43,918 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.
25/00062/FULL6
37, Limes Road, Br3 6ns
Rear extension
Under consideration
–
25/00246/FULL6
106, Bromley Road, Br3 5np
Windows, doors or cladding
Approved
Feb 2025
24/04429/FULL6
1, Ashdown Close, Br3 6tj
Garage conversion or garage
Approved
Dec 2024
24/04167/FULL6
50, The Avenue, Br3 5er
Loft or dormer
Approved
Dec 2024
24/03850/FULL6
11, Greenways, Br3 3ng
Garage conversion or garage
Approved
Aug 2024
24/02505/FULL6
46, Manor Way, Br3 3lj
Windows, doors or cladding
Approved
Jun 2024
24/01403/FULL6
2c, Ridge House, Kemerton Road, Br3 6nj
Loft or dormer
Approved
May 2024
24/00841/FULL6
36, Crescent Road, Br3 6ne
Other householder work
Approved
Apr 2024
24/00538/FULL6
20, Crescent Road, Br3 6ne
Other householder work
Approved
Apr 2024
24/00216/FULL6
32, Wickham Road, Br3 5jt
Other householder work
Approved
Mar 2024
24/00087/FULL6
9, Manor Grove, Br3 5lb
Loft or dormer
Approved
Feb 2024
23/04619/FULL6
38, Overbury Avenue, Br3 6py
Loft or dormer
Refused
Feb 2024
23/04543/FULL6
7, Oakhill Road, Br3 6ng
Two-storey extension
Refused
Jan 2024
23/03879/FULL6
31, The Mead, Br3 5pf
Loft or dormer
Approved
Dec 2023
23/03936/FULL6
15, Greenways, Br3 3ng
Porch or front extension
Approved
Nov 2023
23/03589/FULL6
33, The Mead, Br3 5pf
Garage conversion or garage
Approved
Sept 2023
23/02973/FULL6
36b, Albemarle Road, Br3 5hn
Loft or dormer
Approved
Sept 2023
23/02646/FULL6
3, Stanley Avenue, Br3 6pu
Loft or dormer
Approved
Sept 2023
23/02713/FULL6
12, Kepplestone Mews, Br3 6ax
Loft or dormer
Approved
Sept 2023
23/02683/FULL6
34, Overbury Avenue, Br3 6py
Outbuilding or garden room
Approved
Aug 2023
23/02419/FULL6
7, Greenways, Br3 3ng
Loft or dormer
Approved
Aug 2023
23/02160/FULL6
49, Vine Cottage, Chancery Lane, Br3 6nr
Windows, doors or cladding
Approved
Aug 2023
23/01720/FULL6
90, Overbury Avenue, Br3 6py
Loft or dormer
Approved
Jul 2023
23/01578/FULL6
22, Manor Way, Br3 3lj
Windows, doors or cladding
Approved
Jun 2023
23/01227/FULL6
54, Wickham Road, Br3 6lt
Rear extension
Approved
Jun 2023
23/01368/FULL6
30, Church Avenue, Br3 1dt
Rear extension
Approved
Apr 2023
23/00662/FULL6
12, Kepplestone Mews, Br3 6ax
Basement
Approved
Mar 2023
22/05001/FULL6
44, Kenwood Drive, Br3 6qy
Two-storey extension
Approved
Mar 2023
23/00028/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.
80% (5)
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.