What you could build at W4 5DD: 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 Chiswick North West, Ealing.
263extensions seen within 600 m in the last 10 years
31loft conversions within 600 m in the last 10 years
114.4extensions 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 Chiswick North West.
Move to a home 20 m² bigger (about £1,178,000)
Stamp duty on the new home
£61,550
Estate agent on yours 1.2% + VAT
£14,328
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£80,978
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
−£109,800
Money gone
−£52,300
On these figures, extending loses about £133,278 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.
33, Carlton Road, W4 5dy
Loft or dormer
Approved
Sept 2026
261866HH
33, Kent Road, W4 5ey
Loft or dormer
Approved
Jun 2026
261569HH
33, Kent Road, W4 5ey
Side return or wrap-around
Approved
Jun 2026
261570HH
55, Ramillies Road, W4 1jw
Loft or dormer
Approved
Aug 2026
261571HH
70, Hatfield Road, W4 1af
Rear extension
Approved
Apr 2026
260932HH
16, Berrymede Road, W4 5jf
Loft or dormer
Refused
Apr 2026
260886HH
11, Cunnington Street, W4 5ep
Other householder work
Other
Apr 2026
260904PACBSD
61, Fletcher Road, W4 5at
Loft or dormer
Approved
Apr 2026
260905HH
126, Fielding Road, W4 1db
Rear extension
Approved
May 2026
260833HH
58, Clovelly Road, W4 5ds
Loft or dormer
Approved
Apr 2026
260345HH
10, Brouncker Road, W3 8aq
Loft or dormer
Approved
Mar 2026
260198HH
126, Fielding Road, W4 1db
Rear extension
Refused
Feb 2026
260132PALHE
124, Rusthall Avenue, W4 1bs
Side return or wrap-around
Approved
Mar 2026
260115HH
99, Esmond Road, W4 1je
Windows, doors or cladding
Refused
Mar 2026
260047HH
14, Bridgman Road, W4 5bd
Loft or dormer
Approved
Feb 2026
254739HH
15, Wolseley Road, W4 5eg
Side return or wrap-around
Approved
Mar 2026
254733HH
11, Leythe Road, W3 8aw
Loft or dormer
Approved
Feb 2026
254526HH
19, Rusthall Avenue, W4 1bw
Basement
Approved
Apr 2026
254480HH
106, St Albans Avenue, W4 5jr
Side extension
Approved
Feb 2026
254379HH
49, Antrobus Road, W4 5hz
Loft or dormer
Approved
Jan 2026
254302HH
2, Graham Road, W4 5dr
Loft or dormer
Approved
Mar 2026
254184HH
64, Clovelly Road, W4 5ds
Windows, doors or cladding
Approved
Jan 2026
253312HH
106, St Albans Avenue, W4 5jr
Loft or dormer
Approved
Dec 2025
254089HH
117, Esmond Road, W4 1je
Loft or dormer
Approved
Feb 2026
253586HH
67, Fielding Road, W4 1da
Loft or dormer
Approved
Dec 2025
253896HH
1a, Kingscote Road, W4 5lj
Basement
Approved
Dec 2025
253861HH
43, Beaumont Road, W4 5al
Rear extension
Approved
Jan 2026
253754HH
15, Carlton Road, W4 5dy
Loft or dormer
Approved
Dec 2025
253698HH
5, Brookfield Road, W4 1de
Rear extension
Not needed / lawful
Oct 2025
253578PALHE
39, Marlborough Crescent, W4 1hg
Windows, doors or cladding
Under consideration
–
253503HH
43, Rothschild Road, W4 5ht
Loft or dormer
Approved
Nov 2025
253138HH
98, St Albans Avenue, W4 5jr
Side return or wrap-around
Approved
Oct 2025
253334HH
113, Esmond Road, W4 1je
Windows, doors or cladding
Refused
Apr 2026
244269HH
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% (76)
88%
8 weeks
Basement
–
81% (52)
83%
10 weeks
Porch or front extension
–
80% (64)
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.