What you could build at NW11 0EN: 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 Golders Green North, Barnet.
72extensions seen within 600 m in the last 10 years
11loft conversions within 600 m in the last 10 years
75.3extensions 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.
Not in a conservation area (from council registers).
Article 4 direction (Article 4 Small Houses in Multiple Occupation (HMO) Area 1): some rights normally allowed have been removed here. Check what it covers with the council before relying on permitted development.
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 Golders Green North.
Move to a home 20 m² bigger (about £1,314,000)
Stamp duty on the new home
£75,150
Estate agent on yours 1.2% + VAT
£16,704
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£96,954
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
−£92,400
Money gone
−£34,900
On these figures, extending loses about £131,854 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.
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26/3319/HSE
31, Woodlands, Nw11 9qj
Rear extension
Under consideration
–
26/3320/PNH
134, Bridge Lane, Nw11 9js
Two-storey extension
Under consideration
–
26/3280/HSE
12, Park Way, Nw11 0ex
Rear extension
Refused
Sept 2026
26/3116/PNH
56, Cranbourne Gardens, Nw11 0jd
Loft or dormer
Approved
Oct 2026
26/3005/HSE
14, Cranbourne Gardens, Nw11 0hp
Rear extension
Not needed / lawful
Sept 2026
26/2943/PNH
21, Southbourne Crescent, Nw4 2lb
Loft or dormer
Approved
Aug 2026
26/2613/HSE
12, Park Way, Nw11 0ex
Rear extension
Refused
Aug 2026
26/2518/PNH
113, Princes Park Avenue, Nw11 0js
Two-storey extension
Refused
Aug 2026
26/2520/HSE
14, Cranbourne Gardens, Nw11 0hp
Rear extension
Refused
Aug 2026
26/2471/PNH
13, Monkville Avenue, Nw11 0ah
Two-storey extension
Approved
Aug 2026
26/2474/HSE
10, Eastville Avenue, Nw11 0hd
Two-storey extension
Approved
Aug 2026
26/2331/HSE
38, Green Walk, Nw4 2aj
Two-storey extension
Approved
Jul 2026
26/2401/HSE
30, Fairholme Gardens, N3 3eb
Two-storey extension
Refused
Aug 2026
26/2322/HSE
148, Hampstead Way, Nw11 7xh
Windows, doors or cladding
Approved
Sept 2026
26/1933/HSE
17, Hurstwood Road, Nw11 0as
Rear extension
Not needed / lawful
Jul 2026
26/1962/PNH
57, Princes Park Avenue, Nw11 0jr
Rear extension
Not needed / lawful
Jun 2026
26/1915/PNH
13, Monkville Avenue, Nw11 0ah
Two-storey extension
Refused
Jul 2026
26/1733/HSE
49, Southbourne Crescent, Nw4 2jx
Loft or dormer
Approved
Jun 2026
26/1639/HSE
53, Woodlands, Nw11 9qs
Loft or dormer
Approved
Jul 2026
26/1523/HSE
29, Leeside Crescent, Nw11 0da
Loft or dormer
Approved
Jun 2026
26/1567/HSE
88, Princes Park Avenue, Nw11 0jx
Loft or dormer
Approved
May 2026
26/1529/HSE
14, Cranbourne Gardens, Nw11 0hp
Two-storey extension
Approved
Jun 2026
26/1451/HSE
Geraldene, Greenbank Crescent, Nw4 2la
Two-storey extension
Approved
Jun 2026
26/1213/HSE
30, Fairholme Gardens, N3 3eb
Two-storey extension
Withdrawn
Jun 2026
26/1221/HSE
21, Southbourne Crescent, Nw4 2lb
Loft or dormer
Withdrawn
Jun 2026
26/0989/HSE
42, Woodlands, Nw11 9qu
Porch or front extension
Approved
Apr 2026
26/1024/HSE
29, Leeside Crescent, Nw11 0da
Rear extension
Not needed / lawful
Apr 2026
26/0982/PNH
66, Woodlands, Nw11 9qu
Rear extension
Approved
May 2026
26/0768/HSE
3, Grosvenor Gardens, Nw11 0hh
Loft or dormer
Approved
Apr 2026
26/0739/HSE
38, Eastside Road, Nw11 0ba
Windows, doors or cladding
Approved
Apr 2026
26/0614/HSE
88, Princes Park Avenue, Nw11 0jx
Loft or dormer
Refused
Mar 2026
26/0637/HSE
88, Princes Park Avenue, Nw11 0jx
Loft or dormer
Refused
Mar 2026
26/0661/HSE
38, Eastside Road, Nw11 0ba
Two-storey extension
Approved
Apr 2026
26/0634/HSE
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.
–
94% (157)
88%
8 weeks
Basement
73% (11)
82% (92)
83%
8 weeks
Porch or front extension
–
86% (131)
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.