What you could build at N4 3LQ: 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 Finsbury Park West, Islington.
154extensions seen within 600 m in the last 10 years
30loft conversions within 600 m in the last 10 years
75.5extensions 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).
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.
108a, 3 108a The Coach House, Tollington Park, N4 3rb
Other householder work
Under consideration
–
P2026/1190/FUL
13, Hatley Road, N4 3nn
Rear extension
Approved
–
P2026/0716/FUL
192, Seven Sisters Road, N4 3nx
Loft or dormer
Withdrawn
–
P2026/0767/FUL
39, Eburne Road, N7 6au
Loft or dormer
Approved
May 2026
P2026/0503/FUL
140, Seven Sisters Road, N7 7ns
Other householder work
Withdrawn
–
P2026/0768/PRA
How often householder applications are approved
Work
Finsbury Park West
Islington
London
Typical decision time
All householder applications
60% (5)
76% (204)
80%
8 weeks
Loft or dormer
–
77% (74)
81%
9 weeks
Rear extension
–
91% (23)
79%
8 weeks
Two-storey extension
–
80% (5)
72%
8 weeks
Other householder work
–
63% (49)
70%
8 weeks
Side return or wrap-around
–
–
88%
8 weeks
Windows, doors or cladding
–
86% (21)
90%
8 weeks
Outbuilding or garden room
–
63% (8)
79%
13 weeks
Side extension
–
71% (7)
86%
8 weeks
Garage conversion or garage
–
Cost and the value it adds
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 Finsbury Park West.
Move to a home 20 m² bigger (about £604,000)
Stamp duty on the new home
£20,200
Estate agent on yours 1.2% + VAT
£6,624
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£31,924
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
−£86,400
Money gone
−£28,900
On these figures, extending loses about £60,824 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.
140, Seven Sisters Road, N7 7ns
Other householder work
Withdrawn
–
P2026/0769/PRA
70, Kingsdown Road, N19 4lw
Loft or dormer
Withdrawn
–
P2026/0635/COL
49, Landseer Road, N19 4jr
Loft or dormer
Approved
Apr 2026
P2026/0617/FUL
51, Landseer Road, N19 4jr
Loft or dormer
Approved
–
P2026/0589/FUL
44, Alexander Road, N19 3pq
Side return or wrap-around
Approved
May 2026
P2026/0376/FUL
17, Regina Road, N4 3pt
Rear extension
Approved
Apr 2026
P2026/0132/FUL
14, Corbyn Street, N4 3bz
Loft or dormer
Approved
May 2026
P2026/0404/FUL
46, Eburne Road, N7 6au
Loft or dormer
Approved
Mar 2026
P2026/0395/FUL
14, Corbyn Street, N4 3bz
Loft or dormer
Other
Feb 2026
P2025/2964/COL
65, Sussex Way, N7 6ru
Rear extension
Other
Jan 2026
P2025/2556/COL
52, Alexander Road, N19 3pq
Rear extension
Approved
Jan 2026
P2025/2318/FUL
55, Kingsdown Road, N19 4ld
Other householder work
Withdrawn
–
P2025/2188/FUL
182, Seven Sisters Road, N7 7px
Other householder work
Refused
Oct 2025
P2025/2407/PRA
25, Salterton Road, N7 6bb
Loft or dormer
Approved
Oct 2025
P2025/2398/FUL
144, Hello House, Seven Sisters Road, N7 7ns
Other householder work
Approved
Dec 2025
P2025/2384/PRA
70, Kingsdown Road, N19 4lw
Porch or front extension
Refused
Sept 2025
P2025/2066/FUL
140, Seven Sisters Road, N7 7ns
Other householder work
Refused
Sept 2025
P2025/2214/PRA
88, Corbyn Street, N4 3bz
Loft or dormer
Approved
Oct 2025
P2025/2174/FUL
140, Seven Sisters Road, N7 7ns
Other householder work
Refused
Sept 2025
P2025/2130/PRA
72, 72 Flat C, Hanley Road, N4 3dr
Other householder work
Approved
May 2026
P2025/1246/FUL
4, Falconer Walk, N7 7rq
Rear extension
Withdrawn
–
P2024/2365/COL
Medina Road, N7 7la
Loft or dormer
Refused
Mar 2024
P2024/0034/FUL
Stonenest Street, N4 3ba
Loft or dormer
Approved
Feb 2024
P2024/0038/COLP
19, Almington Street, N4 3bg
Loft or dormer
Other
Jan 2024
P2023/3478/COLP
Ground Floor Flat, Corbyn Street, N4 3bx
Loft or dormer
Refused
Feb 2024
P2023/3484/FUL
47, Medina Road, N7 7la
Outbuilding or garden room
Other
Dec 2023
P2023/2899/COLP
Tollington Way, N7 6rg
Loft or dormer
Other
–
P2023/2756
Landseer Road, N19 4ju
Other householder work
Other
–
P2023/2741
Kingsdown Road, N19 4ld
Loft or dormer
Approved
Feb 2024
P2023/1995/FUL
36, Mitford Road, N19 4hl
Rear extension
Other
Oct 2023
P2023/2629/COLP
94, Thorpedale Road, N4 3bw
Rear extension
Other
Sept 2023
P2023/1663/COLP
9, Whewell Road, N19 4ls
Loft or dormer
Other
Jul 2023
P2023/1569/COLP
108, Thorpedale Road, N4 3bs
Loft or dormer
Other
Jul 2023
P2023/1402/COLP
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.
–
88%
8 weeks
Basement
–
80% (10)
83%
9 weeks
Porch or front extension
–
–
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.