What you could build at W7 1JN: 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 Cuckoo Park, Ealing.
73extensions seen within 600 m in the last 10 years
3loft conversions within 600 m in the last 10 years
64.7extensions 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
Houses usually have permitted development rights: some rear extensions (typically up to 3 m deep for a semi or terrace, 4 m detached), loft conversions within volume limits, and porches can go ahead without planning permission. Larger single-storey rear extensions (up to 6 m / 8 m) can use the “prior approval” neighbour scheme.
In the Cuckoo Estate 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 Cuckoo Park.
Move to a home 20 m² bigger (about £710,000)
Stamp duty on the new home
£25,500
Estate agent on yours 1.2% + VAT
£8,136
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£38,736
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
−£87,000
Money gone
−£29,500
On these figures, extending loses about £68,236 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.
42, Cuckoo Avenue, W7 1bx
Loft or dormer
Approved
Aug 2026
262406HH
29, Beechmount Avenue, W7 3ae
Rear extension
Approved
Aug 2026
262354HH
4, Brookbank Avenue, W7 3dw
Rear extension
Approved
Aug 2026
262359HH
82, Cuckoo Dene, W7 3dr
Two-storey extension
Approved
Aug 2026
262431HH
67, Cuckoo Dene, W7 3dt
Side return or wrap-around
Approved
Jul 2026
262293HH
12, Cuckoo Dene, W7 3dp
Rear extension
Not needed / lawful
Jul 2026
262200PALHE
106, Beechmount Avenue, W7 3aq
Rear extension
Under consideration
–
262174HH
26, Benham Road, W7 1aq
Rear extension
Refused
Jul 2026
262063HH
100, Beresford Avenue, W7 3ap
Rear extension
Approved
Jul 2026
261935HH
26, Benham Road, W7 1aq
Loft or dormer
Approved
Jun 2026
261702HH
67, Cuckoo Dene, W7 3dt
Rear extension
Not needed / lawful
Jun 2026
261687PALHE
293, Greenford Avenue, W7 1ad
Loft or dormer
Approved
Jul 2026
261672HH
40, Elmbank Way, W7 3dg
Loft or dormer
Approved
Jun 2026
261632HH
12, Cuckoo Dene, W7 3dp
Rear extension
Refused
May 2026
261509PALHE
107, Kennedy Road, W7 1jw
Side extension
Approved
May 2026
261459HH
42, Cuckoo Avenue, W7 1bx
Rear extension
Approved
May 2026
261351HH
26, Benham Road, W7 1aq
Porch or front extension
Under consideration
–
261113HH
6, Old Twelve Close, W7 1ja
Loft or dormer
Approved
Apr 2026
260795HH
1, Benham Road, W7 1aq
Two-storey extension
Under consideration
–
260566HH
47, Harp Road, W7 1jg
Loft or dormer
Approved
Apr 2026
260492HH
99, Beresford Avenue, W7 3aj
Rear extension
Not needed / lawful
Nov 2025
253944PALHE
5, Alcott Close, W7 1pe
Rear extension
Approved
Nov 2025
253452HH
47, Harp Road, W7 1jg
Loft or dormer
Refused
Nov 2025
253406HH
178, Westcott Crescent, W7 1pd
Porch or front extension
Approved
Nov 2025
253409HH
54, Harp Road, W7 1jf
Loft or dormer
Approved
Dec 2025
253356HH
426, Greenford Avenue, W7 3db
Two-storey extension
Approved
Jan 2026
253361HH
28, Templeman Road, W7 1at
Rear extension
Refused
Oct 2025
252690FUL
106, Beechmount Avenue, W7 3aq
Rear extension
Refused
Feb 2026
252942HH
30, Greatdown Road, W7 1js
Rear extension
Approved
Sept 2025
252400HH
69, Elmbank Way, W7 3df
Rear extension
Approved
Aug 2025
252263HH
51, Cuckoo Dene, W7 3dt
Garage conversion or garage
Approved
Aug 2025
252044HH
17, Laurie Road, W7 1bl
Two-storey extension
Approved
Nov 2025
251741HH
107, Kennedy Road, W7 1jw
Two-storey extension
Refused
Oct 2025
251702HH
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.