What you could build at SW9 9RY: 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 Acre Lane, Lambeth.
219extensions seen within 600 m in the last 10 years
25loft conversions within 600 m in the last 10 years
141.9extensions 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.
5, 5 Ducie Street London Lambeth Sw4 7rp, Ducie Street, Sw4 7rp
How often householder applications are approved
Work
Acre Lane
Lambeth
London
Typical decision time
All householder applications
75% (36)
78% (1125)
80%
8 weeks
Loft or dormer
89% (18)
89% (593)
81%
8 weeks
Rear extension
–
65% (231)
79%
7 weeks
Two-storey extension
–
80% (10)
72%
8 weeks
Other householder work
–
59% (127)
70%
8 weeks
Side return or wrap-around
67% (6)
60% (45)
88%
8 weeks
Windows, doors or cladding
–
86% (28)
90%
8 weeks
Outbuilding or garden room
–
77% (44)
79%
8 weeks
Side extension
–
76% (21)
86%
8 weeks
Garage conversion or garage
Cost and the value it adds
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 Acre Lane.
Move to a home 20 m² bigger (about £845,000)
Stamp duty on the new home
£32,250
Estate agent on yours 1.2% + VAT
£9,864
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£47,214
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
−£96,000
Money gone
−£38,500
On these figures, extending loses about £85,714 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
Approved
Jun 2026
25/03780/FUL
57, Tasman Road, Sw9 9lz
Loft or dormer
Approved
Apr 2026
26/00157/LDCE
188, Stockwell Road, Sw9 9tf
Loft or dormer
Refused
Mar 2026
26/00112/LDCP
25, 25 Stockwell Green London Lambeth Sw9 9hz, Stockwell Green, Sw9 9hz
83 Hargwyne Street London Lambeth Sw9 9rh, Hargwyne Street, Sw9 9rh
Loft or dormer
Approved
Jun 2025
25/00462/LDCP
35, Tunstall Road, Sw9 8bz
Loft or dormer
Refused
Apr 2025
25/00343/LDCP
22 Stockwell Lane London Lambeth Sw9 0ss
Other householder work
Withdrawn
Jan 2025
24/03740/P20
9 Sidney Road London Lambeth Sw9 0tp
Loft or dormer
Approved
Dec 2024
24/03370/LDCP
146a, 148, Stockwell Road, Sw9 9tq
Other householder work
Refused
Nov 2024
24/02967/P3MA
409, 411, Brixton Road, Sw9 7dg
Other householder work
Refused
Nov 2024
24/02845/P3MA
22 Stockwell Lane London Lambeth Sw9 0ss
Other householder work
Withdrawn
Oct 2024
24/02757/P20
409, 411, Brixton Road, Sw9 7dg
Other householder work
Refused
Sept 2024
24/02108/P3G
174, Ferndale Road, Sw9 8al
Loft or dormer
Refused
Jul 2024
24/01037/LDCP
1, Mordaunt Street, Sw9 9rd
Side return or wrap-around
Refused
Mar 2024
24/00337/LDCP
57 Edithna Street London Lambeth Sw9 9jr
Side extension
Not needed / lawful
Dec 2023
23/03664/PDE
92-94 Landor Road, Development Control Pseudo Street, Sw9 9pe
Other householder work
Approved
Jan 2024
23/03527/P3MA
57, Edithna Street, Sw9 9jr
Loft or dormer
Refused
Nov 2023
23/03475/LDCP
15 Tasman Road London Lambeth Sw9 9lz
Loft or dormer
Approved
Dec 2023
23/03300/LDCP
60, Dalyell Road, Sw9 9up
Side return or wrap-around
Approved
Dec 2023
23/03274/LDCE
5, 5 Glendall Street London Lambeth Sw9 8aj, Glendall Street, Sw9 8aj
Loft or dormer
Approved
Dec 2023
23/03144/FUL
57 Edithna Street London Lambeth Sw9 9jr
Side return or wrap-around
Refused
Oct 2023
23/02685/LDCP
29, Hargwyne Street, Sw9 9rq
Loft or dormer
Approved
Aug 2023
23/01997/LDCP
45, Hargwyne Street, Sw9 9rq
Loft or dormer
Approved
Aug 2023
23/01998/LDCP
170, 170 Stockwell Park Road London Lambeth Sw9 0tn, Stockwell Park Road, Sw9 0tn
Windows, doors or cladding
Approved
Oct 2023
23/01589/FUL
172, 172 Stockwell Park Road London Lambeth Sw9 0tn, Stockwell Park Road, Sw9 0tn
Windows, doors or cladding
Approved
Oct 2023
23/01590/FUL
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% (16)
88%
8 weeks
Basement
–
50% (8)
83%
15 weeks
Porch or front extension
–
–
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.