What you could build at N2 8GA: 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 East Finchley, Barnet.
145extensions seen within 600 m in the last 10 years
16loft conversions within 600 m in the last 10 years
91.8extensions 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 East Finchley.
Move to a home 20 m² bigger (about £913,000)
Stamp duty on the new home
£35,650
Estate agent on yours 1.2% + VAT
£10,944
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£51,694
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
−£91,800
Money gone
−£34,300
On these figures, extending loses about £85,994 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.
79, Hertford Road, N2 9bx
Loft or dormer
Approved
Sept 2026
26/2659/HSE
79, Hertford Road, N2 9bx
Rear extension
Not needed / lawful
Aug 2026
26/2660/PNH
10, Oakview Gardens, N2 0nj
Rear extension
Refused
Sept 2026
26/2492/HSE
86, Brim Hill, N2 0ey
Loft or dormer
Under consideration
–
26/2607/HSE
456, Long Lane, N2 8jl
Rear extension
Refused
Aug 2026
26/2154/HSE
36, Huntingdon Road, N2 9du
Loft or dormer
Approved
Jul 2026
26/2184/HSE
31, Leopold Road, N2 8be
Rear extension
Approved
Jul 2026
26/2136/HSE
43, Leopold Road, N2 8be
Two-storey extension
Withdrawn
Aug 2026
26/1795/HSE
54, Huntingdon Road, N2 9du
Loft or dormer
Approved
Apr 2026
26/0821/HSE
223, Creighton Avenue, N2 9bp
Porch or front extension
Approved
Mar 2026
26/0280/HSE
88, Brim Hill, N2 0ey
Rear extension
Refused
Feb 2026
25/5144/HSE
4, Trinity Avenue, N2 0lx
Two-storey extension
Approved
Jan 2026
25/4983/HSE
228, Creighton Avenue, N2 9bd
Rear extension
Approved
Jan 2026
25/4658/HSE
13, Leicester Road, N2 9dy
Loft or dormer
Approved
Feb 2026
25/4575/HSE
22, Deansway, N2 0jf
Loft or dormer
Approved
Dec 2025
25/4191/HSE
75, Brim Hill, N2 0ez
Loft or dormer
Approved
Dec 2025
25/3723/HSE
5, Park Road, N2 8ex
Loft or dormer
Approved
Nov 2025
25/3956/HSE
67, Leicester Road, N2 9dy
Rear extension
Approved
Nov 2025
25/3893/HSE
143, Abbots Gardens, N2 0jj
Two-storey extension
Approved
Oct 2025
25/3785/HSE
7, Howard Walk, N2 0hb
Windows, doors or cladding
Approved
Nov 2025
25/3707/HSE
19, Chandos Road, N2 9ar
Rear extension
Approved
Oct 2025
25/3628/HSE
65, Bedford Road, N2 9db
Loft or dormer
Approved
Oct 2025
25/3511/HSE
47, Lincoln Road, N2 9dj
Loft or dormer
Approved
Sept 2025
25/3401/HSE
13, Talbot Avenue, N2 0ls
Rear extension
Approved
Oct 2025
25/3403/HSE
95, Huntingdon Road, N2 9dx
Rear extension
Approved
Jul 2025
25/2370/HSE
28, Lincoln Road, N2 9dl
Loft or dormer
Approved
Aug 2025
25/2293/HSE
8, Manor Park Road, N2 0sl
Rear extension
Approved
Jul 2025
25/2177/HSE
32, Manor Park Road, N2 0sj
Rear extension
Approved
Jun 2025
25/1609/HSE
143, Abbots Gardens, N2 0jj
Loft or dormer
Refused
May 2025
25/1317/HSE
31, Baronsmere Road, N2 9qd
Side return or wrap-around
Approved
May 2025
25/1430/HSE
4, Howard Walk, N2 0hb
Loft or dormer
Approved
May 2025
25/1134/HSE
66, Chandos Road, N2 9ap
Loft or dormer
Approved
May 2025
25/1021/HSE
72, Durham Road, N2 9ds
Loft or dormer
Refused
Mar 2025
25/0708/HSE
17, Bedford Road, N2 9db
Loft or dormer
Approved
Mar 2025
25/0324/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.