What you could build at SE20 7HJ: 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 Anerley North & Penge West, Bromley.
76extensions seen within 600 m in the last 10 years
8loft conversions within 600 m in the last 10 years
58.8extensions 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
Mostly flats at this postcode. Flats have no permitted development rights, so almost any extension or loft conversion needs planning permission, and the freeholder's consent under the lease.
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 (126,300 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 Anerley North & Penge West.
Move to a home 20 m² bigger (about £471,000)
Stamp duty on the new home
£13,550
Estate agent on yours 1.2% + VAT
£5,184
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£23,834
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 £32,934 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.
Loft or dormer
Refused
Feb 2025
24/04580/FULL6
25, Crampton Road, Se20 7ar
Loft or dormer
Approved
Jan 2025
24/04302/FULL6
Land Rear Of 100, Venner Road
Other householder work
Approved
Dec 2024
24/03963/TELCOM
60, Crampton Road, Se20 7at
Rear extension
Not needed / lawful
Nov 2024
24/03738/HHPA
Muirhead Vactric, Oakfield Road, Se20 8ew
Other householder work
Approved
Nov 2024
24/03465/DEMCON
22, Raleigh Road, Se20 7jb
Loft or dormer
Approved
Oct 2024
24/03245/FULL6
13, Graveney Grove, Se20 8qg
Windows, doors or cladding
Approved
Jul 2024
24/01885/FULL6
8, Wordsworth Road, Se20 7jg
Loft or dormer
Approved
Sept 2024
24/01744/FULL6
14a, Luxin, Chestnut Grove, Se20 8pd
Other householder work
Approved
Jun 2024
24/01367/FULL6
11, Crampton Road, Se20 7ar
Loft or dormer
Approved
May 2024
24/01276/FULL6
17, Byne Road, Se26 5jf
Side return or wrap-around
Approved
Apr 2024
23/04734/FULL6
3, St Johns Cottages, Maple Road, Se20 8hx
Loft or dormer
Approved
Mar 2024
23/04559/FULL6
5, Southey Street, Se20 7jd
Loft or dormer
Approved
Jan 2024
23/04582/FULL6
24, Albert Road, Se20 7jw
Windows, doors or cladding
Approved
Jan 2024
23/04042/FULL6
25, Kingswood Road, Se20 7bl
Loft or dormer
Approved
Jan 2024
23/04351/FULL6
52, Wiverton Road, Se26 5hy
Rear extension
Approved
Oct 2023
23/03533/HHPA
30, Albert Road, Se20 7jw
Windows, doors or cladding
Approved
Nov 2023
23/03351/FULL6
39, Byne Road, Se26 5jf
Other householder work
Approved
Oct 2023
23/02734/FULL6
5, Southey Street, Se20 7jd
Loft or dormer
Refused
Oct 2023
23/03098/FULL6
20, Byne Road, Se26 5je
Rear extension
Approved
Oct 2023
23/03113/FULL6
33, Wiverton Road, Se26 5ja
Rear extension
Approved
Sept 2023
23/02666/FULL6
33, Raleigh Road, Se20 7je
Rear extension
Approved
Sept 2023
23/02867/FULL6
36, Station Road, Se20 7bq
Loft or dormer
Refused
Sept 2023
23/02753/FULL6
52, Crystal Palace Park Road, Se26 6ug
Loft or dormer
Approved
Sept 2023
23/02382/FULL6
7, Maybourne Close, Se26 6hq
Porch or front extension
Refused
Nov 2023
23/02376/FULL6
29, Maitland Road, Se26 5nn
Loft or dormer
Approved
Aug 2023
23/02204/FULL6
165, Venner Road, Se26 5hx
Loft or dormer
Approved
Aug 2023
23/01989/FULL6
23, Kingswood Road, Se20 7bl
Loft or dormer
Approved
Jun 2023
23/01417/FULL6
22, Chestnut Grove, Se20 8ps
Rear extension
Approved
Jun 2023
23/01412/FULL6
20, Byne Road, Se26 5je
Rear extension
Refused
May 2023
23/01238/FULL6
16a, Wiverton Road, Se26 5hy
Rear extension
Approved
Mar 2023
23/00393/FULL6
25, Trenholme Road, Se20 8pp
Two-storey extension
Approved
Apr 2023
23/00645/FULL6
Oakfield Road Industrial Estate, Europa International, Oakfield Road, Se20 8ra
Other householder work
Approved
Mar 2023
23/00466/TELCOM
3, Alexandra Cottages, Hardings Lane, Se20 7jj
Rear extension
Approved
Aug 2023
23/00181/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.
–
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.