What you could build at SE20 7PF: 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 Penge East, Bromley.
113extensions seen within 600 m in the last 10 years
11loft conversions within 600 m in the last 10 years
99.7extensions 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 (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 Penge East.
Move to a home 20 m² bigger (about £774,000)
Stamp duty on the new home
£28,700
Estate agent on yours 1.2% + VAT
£9,216
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£43,016
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
−£80,400
Money gone
−£22,900
On these figures, extending loses about £65,916 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.
9, Torr Road, Se20 7ps
Rear extension
Approved
Jun 2025
25/01428/FULL6
83, Avenue Road, Br3 4rx
Porch or front extension
Under consideration
–
25/01341/FULL6
34a, Kings Hall Road, Br3 1lu
Rear extension
Under consideration
–
25/00955/FULL6
143, Parish Lane, Se20 7jh
Rear extension
Approved
May 2025
25/00928/FULL6
83, Birkbeck Road, Br3 4sw
Rear extension
Approved
May 2025
25/01018/FULL6
15, Ravenscroft Road, Br3 4tp
Rear extension
Approved
Jun 2025
25/00687/FULL6
36, Reddons Road, Br3 1lz
Two-storey extension
Approved
Apr 2025
25/00462/FULL6
92, Barnmead Road, Br3 1jd
Other householder work
Approved
Apr 2025
25/00210/FULL6
74, Barnmead Road, Br3 1jd
Windows, doors or cladding
Approved
Apr 2025
24/04486/FULL6
15, Ravenscroft Road, Br3 4tp
Rear extension
Approved
Jun 2025
25/00061/FULL6
249, Kent House Road, Br3 1jq
Loft or dormer
Refused
Feb 2025
25/00037/FULL6
9, Whateley Road, Se20 7ne
Rear extension
Approved
Jan 2025
24/04509/FULL6
36, Albert Road, Se20 7jw
Windows, doors or cladding
Approved
Jan 2025
24/03523/FULL6
11, Kingsdale Road, Se20 7pr
Rear extension
Not needed / lawful
Dec 2024
24/03928/HHPA
117, Victor Road, Se20 7jt
Windows, doors or cladding
Approved
Apr 2025
24/04366/FULL6
17, Kings Hall Road, Br3 1lt
Other householder work
Approved
Feb 2025
24/04297/FULL6
50, Ravenscroft Road, Br3 4tr
Rear extension
Approved
Nov 2024
24/04010/FULL6
67, Wordsworth Road, Se20 7jf
Rear extension
Not needed / lawful
Nov 2024
24/03741/HHPA
101, Ravenscroft Road, Br3 4tp
Rear extension
Approved
Nov 2024
24/03598/FULL6
22, Raleigh Road, Se20 7jb
Loft or dormer
Approved
Oct 2024
24/03245/FULL6
34a, Kings Hall Road, Br3 1lu
Two-storey extension
Approved
Sept 2024
24/02897/FULL6
13, Stodart Road, Se20 8et
Loft or dormer
Approved
Sept 2024
24/02909/FULL6
259, Kent House Road, Br3 1jq
Loft or dormer
Approved
Sept 2024
24/02892/FULL6
5, Barnmead Road, Br3 1jf
Side return or wrap-around
Approved
Oct 2024
24/02745/FULL6
249, Kent House Road, Br3 1jq
Side return or wrap-around
Approved
Aug 2024
24/02598/FULL6
42, Kenilworth Road, Se20 7qg
Rear extension
Refused
Sept 2024
24/02580/FULL6
42, Kenilworth Road, Se20 7qg
Loft or dormer
Refused
Sept 2024
24/02567/FULL6
50, Barnmead Road, Br3 1je
Windows, doors or cladding
Approved
Jan 2025
24/01386/FULL6
98, Edward Road, Se20 7js
Windows, doors or cladding
Approved
Aug 2024
24/02085/FULL6
75, Lennard Road, Se20 7ly
Loft or dormer
Approved
Jul 2024
24/02043/FULL6
Sanctuary Court, Croydon Road, Se20 7te
Other householder work
Approved
Jul 2024
24/01901/NDFLAT
29, Ravenscroft Road, Br3 4tp
Loft or dormer
Approved
Jul 2024
24/01908/FULL6
8, Wordsworth Road, Se20 7jg
Loft or dormer
Approved
Sept 2024
24/01744/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.