What you could build at W8 6JH: 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 Kensington Gardens, Kensington and Chelsea.
257extensions seen within 600 m in the last 10 years
26loft conversions within 600 m in the last 10 years
84.4extensions 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
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.
In the Lexham conservation area: permitted development is narrower (for example no side extensions or roof cladding), and demolition and works to trees need consent.
Article 4 direction (Article 4 - No 100): 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 Kensington Gardens.
Move to a home 20 m² bigger (about £1,141,000)
Stamp duty on the new home
£57,850
Estate agent on yours 1.2% + VAT
£13,248
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£76,198
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
−£132,600
Money gone
−£75,100
On these figures, extending loses about £151,298 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.
Apr 2026
PP/25/06573
Development Site At Demolished Avon House, Allen Street, London
Other householder work
Approved
Oct 2025
CL/25/05542
9 Radley Mews, London, W8 6jp
Windows, doors or cladding
Approved
Apr 2026
PP/25/05996
14, 14 Cottesmore Gardens, London, W8 5pr
Basement
Approved
May 2026
PP/25/05254
7 Stanford Road, London, W8 5pp
Other householder work
Approved
Nov 2025
PP/25/05888
27 Ansdell Terrace, London, W8 5by
Other householder work
Approved
Mar 2026
PP/25/05902
44 Abingdon Road, London, W8 6ar
Side return or wrap-around
Approved
Nov 2025
PP/25/05681
56 Adam And Eve Mews, London, W8 6uj
Side return or wrap-around
Approved
Mar 2026
PP/25/06042
8 Cornwall Mews West, London, Sw7 4bh
Other householder work
Approved
Mar 2026
PP/25/05733
10 Cottesmore Gardens, London, W8 5pr
Windows, doors or cladding
Approved
Nov 2025
PP/25/05723
7 Eldon Road, London, W8 5pu
Rear extension
Approved
Apr 2026
PP/25/05974
7 Alma Terrace, Allen Street, London, W8 6qy
Other householder work
Approved
Mar 2026
PP/25/05848
Hotel, 147c Cromwell Road, London, Sw5 0th
Other householder work
Approved
Apr 2026
CL/25/05819
33a Pembroke Road, London, W8 6pd
Other householder work
Approved
Apr 2026
CL/25/05757
25 Courtfield Gardens, London, Sw5 0pg
Other householder work
Approved
Nov 2025
CL/25/05320
38 Kelso Place, London, W8 5qp
Basement
Approved
Apr 2026
PP/25/05420
Development Site, 201-207 Kensington High Street, London
Other householder work
Approved
Sept 2025
CL/25/05151
20, 20 Adam And Eve Mews, London, W8 6uj
Loft or dormer
Approved
Oct 2025
PP/25/04883
35, 35 Kynance Mews, London, Sw7 4qr
Windows, doors or cladding
Approved
Oct 2025
PP/25/05174
9, 9 Colbeck Mews, London, Sw7 4lx
Garage conversion or garage
Approved
Oct 2025
PP/25/05175
3 Shaftesbury Villas, Allen Street, London, W8 6uz
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
67% (6)
–
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.