What you could build at NW9 7EE: 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 West Hendon, Barnet.
74extensions seen within 600 m in the last 10 years
6loft conversions within 600 m in the last 10 years
45.3extensions 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
Mostly flats at this postcode. Flats have no permitted development rights, so almost any extension or loft conversion needs planning permission, and the freeholder's consent under the lease.
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 West Hendon.
Move to a home 20 m² bigger (about £505,000)
Stamp duty on the new home
£15,250
Estate agent on yours 1.2% + VAT
£5,760
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£26,110
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
−£63,000
Money gone
−£5,500
On these figures, extending loses about £31,610 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.
27, Riverside, Nw4 3tu
Rear extension
Not needed / lawful
Jun 2026
26/1906/PNH
6, Cool Oak Lane, Nw9 7bj
Side return or wrap-around
Refused
Jun 2026
26/1467/HSE
14, Cool Oak Lane, Nw9 7bj
Two-storey extension
Approved
May 2026
26/0972/HSE
4, Riverside, Nw4 3tx
Two-storey extension
Approved
Apr 2026
26/0942/HSE
6, Cool Oak Lane, Nw9 7bj
Side return or wrap-around
Approved
Apr 2026
26/0516/HSE
14, Cool Oak Lane, Nw9 7bj
Loft or dormer
Withdrawn
Mar 2026
26/0159/HSE
21, Woolmead Avenue, Nw9 7ba
Rear extension
Approved
Mar 2026
26/0238/HSE
64, Woolmead Avenue, Nw9 7ay
Two-storey extension
Approved
Feb 2026
25/5046/HSE
21, Woolmead Avenue, Nw9 7ba
Rear extension
Refused
Jan 2026
25/5039/PNH
67, Dallas Road, Nw4 3jd
Rear extension
Approved
Jan 2026
25/4949/PNH
64, Woolmead Avenue, Nw9 7ay
Rear extension
Not needed / lawful
Dec 2025
25/4659/PNH
64, Woolmead Avenue, Nw9 7ay
Loft or dormer
Withdrawn
Dec 2025
25/4663/HSE
16, Layfield Crescent, Nw4 3ul
Rear extension
Not needed / lawful
Dec 2025
25/4571/PNH
4, Riverside, Nw4 3tx
Loft or dormer
Refused
Jan 2026
25/4250/HSE
14, Cool Oak Lane, Nw9 7bj
Rear extension
Not needed / lawful
Dec 2025
25/4404/PNH
12, Dartmouth Road, Nw4 3hu
Rear extension
Approved
Sept 2025
25/3427/HSE
11, Foscote Road, Nw4 3se
Side return or wrap-around
Approved
Aug 2025
25/2712/HSE
31, Riverside, Nw4 3tu
Rear extension
Not needed / lawful
Apr 2025
25/1186/PNH
19, Riverside, Nw4 3tu
Two-storey extension
Approved
Apr 2025
25/0902/HSE
20, Cool Oak Lane, Nw9 7bj
Rear extension
Approved
Mar 2025
25/0409/HSE
87, Sturgess Avenue, Nw4 3tr
Outbuilding or garden room
Approved
Mar 2025
25/0277/HSE
8, Brent View Road, Nw9 7eh
Rear extension
Approved
Mar 2025
25/0185/HSE
23, Dartmouth Road, Nw4 3ja
Rear extension
Refused
Feb 2025
24/5477/HSE
64, Woolmead Avenue, Nw9 7ay
Rear extension
Approved
Jan 2025
24/4589/HSE
49, Riverside, Nw4 3tu
Two-storey extension
Refused
Dec 2024
24/4434/HSE
16, Layfield Crescent, Nw4 3ul
Two-storey extension
Refused
Jan 2025
24/4178/HSE
6, Cool Oak Lane, Nw9 7bj
Side return or wrap-around
Refused
Oct 2024
24/3208/HSE
34, Woolmead Avenue, Nw9 7ay
Rear extension
Withdrawn
Sept 2024
24/3112/PNH
23, Dartmouth Road, Nw4 3ja
Rear extension
Approved
Sept 2024
24/3058/HSE
61, Russell Road, Nw9 6ab
Loft or dormer
Withdrawn
Sept 2024
24/2897/HSE
49, Riverside, Nw4 3tu
Rear extension
Not needed / lawful
Aug 2024
24/2845/PNH
19, Riverside, Nw4 3tu
Two-storey extension
Refused
Sept 2024
24/2685/HSE
324, West Hendon Broadway, Nw9 6ae
Loft or dormer
Approved
Aug 2024
24/2465/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.