What you could build at NW2 1SP: 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 Childs Hill, Barnet.
100extensions seen within 600 m in the last 10 years
9loft conversions within 600 m in the last 10 years
78.6extensions 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).
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 Childs Hill.
Move to a home 20 m² bigger (about £737,000)
Stamp duty on the new home
£26,850
Estate agent on yours 1.2% + VAT
£8,568
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£40,518
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
−£85,200
Money gone
−£27,700
On these figures, extending loses about £68,218 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.
90, Cheviot Gardens, Nw2 1qa
Loft or dormer
Refused
Jun 2026
26/1796/HSE
58, Caddington Road, Nw2 1rs
Rear extension
Withdrawn
Jul 2026
26/1785/HSE
23, Sanderstead Avenue, Nw2 1se
Loft or dormer
Approved
Sept 2026
26/1701/HSE
20, Sanderstead Avenue, Nw2 1sg
Loft or dormer
Approved
Jun 2026
26/1621/HSE
22, Somerton Road, Nw2 1sa
Rear extension
Approved
Jun 2026
26/1183/HSE
30, Dersingham Road, Nw2 1sl
Loft or dormer
Refused
Jun 2026
26/1475/HSE
138, The Vale, Nw11 8sn
Other householder work
Approved
Jun 2026
26/1125/HSE
90, Cheviot Gardens, Nw2 1qa
Rear extension
Approved
Apr 2026
26/1012/PNH
62, Greenfield Gardens, Nw2 1hy
Rear extension
Not needed / lawful
Apr 2026
26/0968/PNH
16, Harman Drive, Nw2 2eb
Loft or dormer
Approved
Apr 2026
26/0766/HSE
94, Cloister Road, Nw2 2np
Loft or dormer
Approved
Mar 2026
26/0575/HSE
Brendon, Lyndale, Nw2 2ny
Loft or dormer
Approved
Mar 2026
26/0358/HSE
16, Harman Drive, Nw2 2eb
Loft or dormer
Refused
Feb 2026
26/0240/PNH
22, Somerton Road, Nw2 1sa
Rear extension
Refused
Feb 2026
26/0222/PNH
30, Dersingham Road, Nw2 1sl
Loft or dormer
Refused
Mar 2026
26/0043/HSE
23, Sanderstead Avenue, Nw2 1se
Loft or dormer
Refused
Feb 2026
25/4880/HSE
304, Cricklewood Lane, Nw2 2px
Two-storey extension
Approved
Mar 2026
25/5065/HSE
40, Galsworthy Road, Nw2 2sb
Rear extension
Approved
Jan 2026
25/4656/PNH
30, Dersingham Road, Nw2 1sl
Rear extension
Refused
Dec 2025
25/4819/PNH
12, Harman Drive, Nw2 2eb
Loft or dormer
Approved
Jan 2026
25/4595/HSE
117, Granville Road, Nw2 2er
Rear extension
Refused
Jan 2026
25/4549/HSE
23, Sanderstead Avenue, Nw2 1se
Rear extension
Approved
Jan 2026
25/4525/PNH
67, Hendon Way, Nw2 2ly
Loft or dormer
Approved
Dec 2025
25/4348/HSE
23, Sanderstead Avenue, Nw2 1se
Rear extension
Refused
Nov 2025
25/3987/PNH
102, Cheviot Gardens, Nw2 1qa
Rear extension
Not needed / lawful
Oct 2025
25/3902/PNH
94, Cloister Road, Nw2 2np
Two-storey extension
Approved
Nov 2025
25/3820/HSE
94, Cloister Road, Nw2 2np
Rear extension
Not needed / lawful
Oct 2025
25/3823/PNH
304, Cricklewood Lane, Nw2 2px
Other householder work
Refused
Oct 2025
25/3156/HSE
102, Cheviot Gardens, Nw2 1qa
Rear extension
Approved
Sept 2025
25/3225/HSE
31, Somerton Road, Nw2 1rj
Rear extension
Approved
Sept 2025
25/3197/HSE
4, Sanderstead Avenue, Nw2 1sg
Side return or wrap-around
Approved
Sept 2025
25/2897/HSE
21, Oak Grove, Nw2 3ls
Loft or dormer
Approved
Aug 2025
25/2729/HSE
304, Cricklewood Lane, Nw2 2px
Rear extension
Not needed / lawful
Jul 2025
25/2449/PNH
107, Hendon Way, Nw2 2ly
Loft or dormer
Approved
Jul 2025
25/2478/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
–
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.