What you could build at NW11 0AS: 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.
73extensions seen within 600 m in the last 10 years
11loft conversions within 600 m in the last 10 years
77extensions 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 (126,300 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.
134, Bridge Lane, Nw11 9js
Two-storey extension
Under consideration
–
26/3280/HSE
25, Beechwood Avenue, N3 3au
Two-storey extension
Approved
Oct 2026
26/3196/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
Highview, Chessington Avenue, N3 3dp
Loft or dormer
Withdrawn
Oct 2026
26/2872/HSE
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
30, Fairholme Gardens, N3 3eb
Two-storey extension
Refused
Aug 2026
26/2322/HSE
8, Allandale Avenue, N3 3pj
Rear extension
Refused
Aug 2026
26/2165/HSE
17, Hurstwood Road, Nw11 0as
Rear extension
Not needed / lawful
Jul 2026
26/1962/PNH
13, Monkville Avenue, Nw11 0ah
Two-storey extension
Refused
Jul 2026
26/1733/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
38, Eastside Road, Nw11 0ba
Windows, doors or cladding
Approved
Apr 2026
26/0614/HSE
8, Allandale Avenue, N3 3pj
Rear extension
Refused
Mar 2026
26/0629/PNH
38, Eastside Road, Nw11 0ba
Two-storey extension
Approved
Apr 2026
26/0634/HSE
92, Princes Park Avenue, Nw11 0jx
Loft or dormer
Approved
Apr 2026
26/0427/HSE
50, Ashbourne Avenue, Nw11 0ds
Side return or wrap-around
Approved
Mar 2026
26/0468/HSE
22, Monkville Avenue, Nw11 0ah
Basement
Approved
Mar 2026
26/0209/HSE
28, Chessington Avenue, N3 3dp
Loft or dormer
Approved
Feb 2026
26/0184/HSE
30, Fairholme Gardens, N3 3eb
Loft or dormer
Approved
Feb 2026
25/5190/HSE
38, Asmuns Hill, Nw11 6et
Windows, doors or cladding
Approved
Feb 2026
25/4688/HSE
36, Hogarth Hill, Nw11 6ba
Windows, doors or cladding
Under consideration
–
25/4578/HSE
56, Cranbourne Gardens, Nw11 0jd
Two-storey extension
Approved
Mar 2026
25/4456/HSE
46, Addison Way, Nw11 6as
Loft or dormer
Approved
Dec 2025
25/4337/HSE
15, Haslemere Gardens, N3 3ea
Rear extension
Refused
Nov 2025
25/4008/PNH
8, Hallswelle Road, Nw11 0dj
Rear extension
Approved
Nov 2025
25/3736/HSE
17, Ashbourne Avenue, Nw11 0dp
Side return or wrap-around
Approved
Sept 2025
25/2912/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.