What you could build at TW9 3LU: 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 Kew Gardens, Richmond upon Thames.
118extensions seen within 600 m in the last 10 years
11loft conversions within 600 m in the last 10 years
106.9extensions 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.
In the Kew Gardens 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 Kew Gardens.
Move to a home 20 m² bigger (about £1,266,000)
Stamp duty on the new home
£70,350
Estate agent on yours 1.2% + VAT
£15,480
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£90,930
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
−£114,600
Money gone
−£57,100
On these figures, extending loses about £148,030 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.
2, Hatherley Road, Tw9 3lh
Rear extension
Approved
Sept 2026
PA26/2578
14, Beechwood Avenue, Tw9 4de
Loft or dormer
Approved
Sept 2026
PA26/2661
45, Ennerdale Road, Tw9 2dn
Windows, doors or cladding
Approved
Sept 2026
PA26/2465
25, Lawn Crescent, Tw9 3ns
Other householder work
Approved
Aug 2026
PA26/2037
20, Chilton Road, Tw9 4jb
Rear extension
Approved
Jul 2026
PA26/2355
47, Sandycombe Road, Tw9 2ep
Outbuilding or garden room
Approved
Aug 2026
PA26/2265
3, Beechwood Avenue, Tw9 4dd
Other householder work
Approved
Aug 2026
PA26/2324
6, Lichfield Road, Tw9 3jr
Rear extension
Approved
Aug 2026
PA26/2152
40, Beechwood Avenue, Tw9 4de
Rear extension
Approved
Aug 2026
PA26/2032
66, Ennerdale Road, Tw9 2dl
Garage conversion or garage
Approved
Jul 2026
PA26/1850
249, Sandycombe Road, Tw9 3lu
Rear extension
Approved
Jun 2026
PA26/1854
36, Pensford Avenue, Tw9 4hp
Rear extension
Approved
Jun 2026
PA26/1688
112, Ennerdale Road, Tw9 2dh
Outbuilding or garden room
Under consideration
–
PA26/1544
64, Burlington Avenue, Tw9 4dh
Other householder work
Under consideration
–
PA26/1131
Kew Gardens 2, Kew Road (A307), Tw9 2ag
Other householder work
Under consideration
–
PA26/1100
31, Burlington Avenue, Tw9 4df
Rear extension
Approved
Apr 2026
PA26/0970
45, North Road, Tw9 4hd
Loft or dormer
Other
May 2026
PA26/0753
3, Alexandra Road, Tw9 2bt
Windows, doors or cladding
Approved
Apr 2026
PA26/0691
22, Taylor Avenue, Tw9 4ed
Loft or dormer
Approved
Apr 2026
PA26/0645
36, Pensford Avenue, Tw9 4hp
Loft or dormer
Other
May 2026
PA26/0665
36, Pensford Avenue, Tw9 4hp
Rear extension
Approved
Apr 2026
PA26/0666
4a, North Avenue, Tw9 3lz
Loft or dormer
Under consideration
–
PA26/0576
27, The Avenue, Tw9 2al
Rear extension
Approved
Apr 2026
PA26/0466
98, Thompson Avenue, Tw9 4jn
Rear extension
Other
Mar 2026
PA26/0392
26, Leyborne Park, Tw9 3ha
Loft or dormer
Approved
Mar 2026
PA26/0281
98, Thompson Avenue, Tw9 4jn
Rear extension
Approved
Mar 2026
PA26/0230
No. 69 And 71 Thompson Avenue, Tw9 4jn
Other householder work
Approved
Apr 2026
PA26/0123
27, West Park Road, Tw9 4db
Garage conversion or garage
Approved
Feb 2026
PA26/0046
24, Leyborne Park, Tw9 3ha
Rear extension
Approved
Feb 2026
PA25/4556
161, Sandycombe Road, Tw9 2en
Loft or dormer
Approved
Feb 2026
PA25/4590
11, Paxton Close, Tw9 2aw
Rear extension
Approved
Feb 2026
PA25/4593
6, Clarence Road, Tw9 3nl
Side return or wrap-around
Approved
Mar 2026
PA25/4532
66, The Avenue, Tw9 2ah
Garage conversion or garage
Approved
Jan 2026
PA25/4354
11, High Park Road, Tw9 4bl
Loft or dormer
Approved
Jan 2026
PA25/4332
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%
8 weeks
Basement
91% (11)
–
83%
9 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.