What you could build at N9 9PN: 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 Haslebury North, Enfield.
83extensions seen within 600 m in the last 10 years
8loft conversions within 600 m in the last 10 years
86.4extensions 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 (Borough wide): 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 Haslebury North.
Move to a home 20 m² bigger (about £546,000)
Stamp duty on the new home
£17,300
Estate agent on yours 1.2% + VAT
£6,336
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£28,736
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
−£63,600
Money gone
−£6,100
On these figures, extending loses about £34,836 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.
Approved
Aug 2026
26/02474/HOU
51, Delhi Road, En1 2lz
Rear extension
Not needed / lawful
Jul 2026
26/02505/PRH
126, Latymer Road, N9 9pw
Other householder work
Approved
Jul 2026
26/01510/HOU
54, Rugby Avenue, N9 9ep
Rear extension
Not needed / lawful
Jun 2026
26/02058/PRH
21, Delhi Road, En1 2lz
Two-storey extension
Approved
Jun 2026
26/01677/HOU
126, Chichester Road, N9 9dg
Rear extension
Not needed / lawful
Apr 2026
26/01222/PRH
181, Latymer Road, N9 9pn
Rear extension
Approved
Apr 2026
26/00659/HOU
181, Latymer Road, N9 9pn
Loft or dormer
Approved
Apr 2026
26/00661/HOU
119, Bury Street, N9 7jp
Rear extension
Not needed / lawful
Mar 2026
26/00531/PRH
30, Kenwood Road, N9 7jd
Rear extension
Not needed / lawful
Jan 2026
25/04312/PRH
60, St Edmunds Road, N9 7pt
Loft or dormer
Approved
Feb 2026
25/04143/HOU
20, Winchester Road, N9 9eb
Rear extension
Not needed / lawful
Jan 2026
25/04183/PRH
30, Crawley Road, En1 2ng
Rear extension
Not needed / lawful
Dec 2025
25/03938/PRH
315, Bury Street West, N9 9jn
Rear extension
Approved
Dec 2025
25/03430/HOU
67, Latymer Road, N9 9pq
Side extension
Approved
Jan 2026
25/03609/HOU
140, Winchester Road, N9 9ef
Rear extension
Not needed / lawful
Nov 2025
25/03438/PRH
28, Galliard Road, N9 7pb
Rear extension
Approved
Nov 2025
25/03439/PRH
173, Wellington Road, En1 2rl
Two-storey extension
Approved
Nov 2025
25/03308/HOU
60, St Edmunds Road, N9 7pt
Two-storey extension
Approved
Nov 2025
25/03273/HOU
12, Delhi Road, En1 2nb
Loft or dormer
Approved
Nov 2025
25/02827/HOU
49, Church Lane, N9 9pz
Loft or dormer
Approved
Oct 2025
25/02708/HOU
256, Bury Street West, N9 9lb
Other householder work
Refused
Nov 2025
25/03057/HOU
144, Croyland Road, N9 7bd
Rear extension
Not needed / lawful
Oct 2025
25/02330/PRH
12, Delhi Road, En1 2nb
Rear extension
Not needed / lawful
Oct 2025
25/02828/PRH
21, Delhi Road, En1 2lz
Two-storey extension
Refused
Sept 2025
25/02426/HOU
173, Wellington Road, En1 2rl
Two-storey extension
Approved
Sept 2025
25/02567/HOU
173, Wellington Road, En1 2rl
Rear extension
Not needed / lawful
Aug 2025
25/02475/PRH
30, Richmond Crescent, N9 7qj
Rear extension
Approved
Aug 2025
25/02416/PRH
131, Amberley Road, En1 2rb
Rear extension
Approved
Sept 2025
25/02120/HOU
2, Stowe Gardens, N9 9ps
Loft or dormer
Refused
Aug 2025
25/02100/HOU
130, Church Street, N9 9as
Other householder work
Refused
Aug 2025
25/02152/HOU
44, Galliard Road, N9 7pb
Rear extension
Approved
Jul 2025
25/02052/HOU
13, Wimborne Road, N9 9ez
Rear extension
Approved
Jun 2025
25/01579/PRH
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.
–
85% (116)
88%
7 weeks
Basement
–
53% (17)
83%
8 weeks
Porch or front extension
–
88% (74)
81%
7 weeks
Share of decided applications approved since 2023 (number decided in brackets). Withdrawn applications aren't counted; many are withdrawn when refusal looks likely.