What you could build at BR1 3QJ: 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 Bromley North & Sundridge, Bromley.
106extensions seen within 600 m in the last 10 years
12loft conversions within 600 m in the last 10 years
87.8extensions 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 Bromley North & Sundridge.
Move to a home 20 m² bigger (about £561,000)
Stamp duty on the new home
£18,050
Estate agent on yours 1.2% + VAT
£6,480
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£29,630
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
−£66,600
Money gone
−£9,100
On these figures, extending loses about £38,730 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.
Approved
May 2025
25/01266/FULL6
46, Crescent Road, Br1 3pw
Rear extension
Approved
Mar 2025
25/00250/FULL6
7, North Street, Br1 1sb
Loft or dormer
Approved
Jan 2025
24/04530/FULL6
67, Plaistow Grove, Br1 3pb
Side extension
Approved
Jan 2025
24/03926/FULL6
61, Plaistow Grove, Br1 3pb
Rear extension
Refused
Jan 2025
24/04465/FULL6
13, College Road, Br1 3pt
Rear extension
Not needed / lawful
Nov 2024
24/03748/HHPA
48, Park Avenue, Br1 4ee
Other householder work
Approved
Nov 2024
24/03600/FULL6
12, Farwig Lane, Br1 3rb
Other householder work
Refused
Oct 2024
24/03361/TELCOM
48, Park Avenue, Br1 4ee
Other householder work
Approved
Oct 2024
24/03190/FULL6
33, Lansdowne Road, Br1 3pg
Loft or dormer
Approved
Aug 2024
24/02313/FULL6
9, Park End, Br1 4an
Side extension
Approved
Jul 2024
24/02112/FULL6
56, Crescent Road, Br1 3pw
Rear extension
Approved
Aug 2024
24/02126/FULL6
40, West Street, Br1 1rf
Loft or dormer
Approved
Jul 2024
24/01967/FULL6
40, West Street, Br1 1rf
Loft or dormer
Withdrawn
Jul 2024
24/01968/FULL6
40, West Street, Br1 1rf
Loft or dormer
Withdrawn
Jul 2024
24/01969/FULL6
57, Park Avenue, Br1 4eg
Side return or wrap-around
Approved
Jul 2024
24/01948/FULL6
61, Plaistow Grove, Br1 3pb
Loft or dormer
Withdrawn
Jul 2024
24/01833/FULL6
54, Lansdowne Road, Br1 3pq
Loft or dormer
Approved
May 2024
24/01149/FULL6
11, Morgan Road, Br1 3qe
Rear extension
Approved
Jul 2024
24/00521/FULL6
4, College Road, Br1 3ns
Rear extension
Approved
Apr 2024
24/00575/FULL6
122, Babbacombe Road, Br1 3lt
Rear extension
Not needed / lawful
Mar 2024
24/00586/HHPA
5, Bromley Avenue, Br1 4bg
Garage conversion or garage
Approved
Mar 2024
24/00280/FULL6
11, Kinnaird Avenue, Br1 4hg
Rear extension
Approved
Jan 2024
23/04628/FULL6
25, Heathfield Road, Br1 3rn
Side return or wrap-around
Approved
Dec 2023
23/04261/FULL6
36, Plaistow Grove, Br1 3pb
Outbuilding or garden room
Approved
Nov 2023
23/03504/FULL6
74, Babbacombe Road, Br1 3lw
Rear extension
Approved
Nov 2023
23/03265/FULL6
15, Plaistow Grove, Br1 3pb
Rear extension
Refused
Oct 2023
23/03358/HHPA
14, Howard Road, Br1 3qj
Loft or dormer
Approved
Nov 2023
23/03219/FULL6
66, Park End, Br1 4aw
Rear extension
Approved
Oct 2023
23/02927/FULL6
2, Florence Road, Br1 3nu
Loft or dormer
Approved
Sept 2023
23/02708/FULL6
48, Park Avenue, Br1 4ee
Outbuilding or garden room
Approved
Jan 2024
23/02641/FULL6
48, Park Avenue, Br1 4ee
Other householder work
Refused
Jan 2024
23/02642/FULL6
40, Plaistow Grove, Br1 3pb
Side extension
Approved
Aug 2023
23/02621/FULL6
104, College Road, Br1 3pf
Rear extension
Not needed / lawful
Aug 2023
23/02579/HHPA
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.
–
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.