What you could build at EN5 3DB: 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 Totteridge & Barnet Gate, Barnet.
30extensions seen within 600 m in the last 10 years
1loft conversions within 600 m in the last 10 years
123extensions 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 Totteridge & Barnet Gate.
Move to a home 20 m² bigger (about £1,270,000)
Stamp duty on the new home
£70,750
Estate agent on yours 1.2% + VAT
£16,056
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£91,906
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
−£93,000
Money gone
−£35,500
On these figures, extending loses about £127,406 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.
Aug 2026
26/2461/HSE
7, Field End, En5 3ez
Loft or dormer
Approved
Aug 2026
26/2367/HSE
5, Oaklands Lane, En5 3jn
Two-storey extension
Approved
Aug 2026
26/2246/HSE
31, Garthland Drive, En5 3bd
Garage conversion or garage
Approved
Aug 2026
26/2180/HSE
27, Elmbank Avenue, En5 3du
Porch or front extension
Approved
May 2026
26/1210/HSE
23, Ryecroft Crescent, En5 3bp
Two-storey extension
Refused
May 2026
26/0986/HSE
13, Raebarn Gardens, En5 3db
Loft or dormer
Approved
Apr 2026
26/0803/HSE
5, Oaklands Lane, En5 3jn
Two-storey extension
Approved
Mar 2026
26/0367/HSE
89, Well Road, En5 3ea
Two-storey extension
Approved
Mar 2026
26/0278/HSE
27, Elmbank Avenue, En5 3du
Porch or front extension
Refused
Mar 2026
26/0246/HSE
136, Barnet Road, En5 3lj
Rear extension
Approved
Jan 2026
25/4833/HSE
95, Quinta Drive, En5 3da
Other householder work
Refused
Dec 2025
25/4740/PNU
89, Well Road, En5 3ea
Rear extension
Approved
Dec 2025
25/4185/HSE
7, Field End, En5 3ez
Loft or dormer
Refused
Oct 2025
25/3392/HSE
53, The Maples, Barnet Road, En5 3hb
Loft or dormer
Approved
Oct 2025
25/3181/HSE
6, Kerri Close, En5 3er
Loft or dormer
Approved
Sept 2025
25/3112/HSE
31, Garthland Drive, En5 3bd
Garage conversion or garage
Approved
Aug 2025
25/2566/HSE
56, Ryecroft Crescent, En5 3bu
Rear extension
Approved
Jul 2025
25/2488/PNH
Tudor House, Arkley Drive, En5 3ln
Outbuilding or garden room
Approved
Jul 2025
25/2320/HSE
25, Ryecroft Crescent, En5 3bp
Two-storey extension
Approved
Jul 2025
25/2070/HSE
5, Arkley View, En5 3jp
Loft or dormer
Refused
Jun 2025
25/1548/HSE
Ridings Lodge, Hedgerow Lane, En5 3dt
Loft or dormer
Refused
May 2025
25/1169/HSE
15, Elmbank Avenue, En5 3du
Outbuilding or garden room
Approved
Jun 2025
25/1100/HSE
Totteridge View, Hedgerow Lane, En5 3dt
Rear extension
Approved
May 2025
25/0909/HSE
45, Ryecroft Crescent, En5 3bu
Two-storey extension
Approved
Apr 2025
25/0875/HSE
57, Thornbury, Barnet Road, En5 3hb
Garage conversion or garage
Refused
Apr 2025
25/0414/HSE
Toorak, Arkley Lane, En5 3jw
Rear extension
Approved
Mar 2025
25/0325/HSE
39, Garthland Drive, En5 3bd
Loft or dormer
Approved
Feb 2025
24/5544/HSE
13, Raebarn Gardens, En5 3db
Two-storey extension
Approved
Feb 2025
24/5567/HSE
70, Tilers Way, Barnet Road, En5 3ha
Garage conversion or garage
Refused
Jan 2025
24/4974/HSE
13, Malins Close, En5 3ax
Outbuilding or garden room
Approved
Dec 2024
24/4477/HSE
36, Endersby Road, En5 3aj
Rear extension
Not needed / lawful
Sept 2024
24/3245/PNH
Equinox, Oaklands Lane, En5 3jn
Basement
Approved
Oct 2024
24/3186/HSE
11, Vyse Close, En5 3ba
Garage conversion or garage
Approved
Aug 2024
24/2507/HSE
1, Arkley Lane, En5 3jr
Rear extension
Approved
Aug 2024
24/2471/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.
Garage conversion or garage
70% (10)
94% (157)
88%
8 weeks
Basement
–
82% (92)
83%
8 weeks
Porch or front extension
71% (7)
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.