What you could build at TW4 5LR: 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 Heathfield, Richmond upon Thames.
48extensions seen within 600 m in the last 10 years
1loft conversions within 600 m in the last 10 years
102.3extensions 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
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).
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.
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 Heathfield.
Move to a home 20 m² bigger (about £723,000)
Stamp duty on the new home
£26,150
Estate agent on yours 1.2% + VAT
£8,640
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£39,890
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
−£73,800
Money gone
−£16,300
On these figures, extending loses about £56,190 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.
687, Hanworth Road, Tw4 5ps
Side return or wrap-around
Approved
Aug 2026
PA26/1878
9, Conway Road, Tw4 5ll
Loft or dormer
Under consideration
–
PA26/2315
169, Powder Mill Lane, Tw2 6eq
Two-storey extension
Under consideration
–
PA26/1637
9, Conway Road, Tw4 5ll
Two-storey extension
Under consideration
–
PA26/1416
174, Waverley Avenue, Tw2 6dl
Rear extension
Under consideration
–
PA26/1153
26, Collingwood Close, Tw2 7af
Rear extension
Approved
–
PA26/1329
244, Lyndhurst Avenue, Tw2 6bp
Rear extension
Other
May 2026
PA26/1285
248, Lyndhurst Avenue, Tw2 6bp
Rear extension
Under consideration
–
PA26/0910
37, Curtis Road, Tw4 5pu
Outbuilding or garden room
Approved
Apr 2026
PA26/0321
169, Powder Mill Lane, Tw2 6eq
Rear extension
Approved
Mar 2026
PA25/4383
20, Harvey Road, Tw4 5lu
Side return or wrap-around
Approved
Mar 2026
PA26/0147
29, Conway Road, Tw4 5ll
Outbuilding or garden room
Other
Mar 2026
PA25/4452
29, Conway Road, Tw4 5ll
Outbuilding or garden room
Other
Dec 2025
PA25/3177
10, Redfern Avenue, Tw4 5ly
Two-storey extension
Under consideration
–
PA25/3309
321, Nelson Road, Tw2 7ag
Two-storey extension
Approved
Oct 2025
PA25/3037
9, Curtis Road, Tw4 5pu
Loft or dormer
Under consideration
–
PA25/2743
10, Redfern Avenue, Tw4 5ly
Two-storey extension
Other
Aug 2025
PA25/2131
16, Harvey Road, Tw4 5lu
Garage conversion or garage
Other
Aug 2025
PA25/1758
59, Nelson Gardens, Tw3 3uj
Garage conversion or garage
Approved
Aug 2025
PA25/2057
534, Hanworth Road, Tw4 5lh
Rear extension
Approved
Jun 2025
PA25/1095
16, Harvey Road, Tw4 5lu
Loft or dormer
Other
Jun 2025
PA25/0634
321, Nelson Road, Tw2 7ag
Two-storey extension
Other
May 2025
PA25/0904
401, Nelson Road, Tw3 3up
Garage conversion or garage
Approved
May 2025
PA25/0775
38, Heathside, Tw4 5nn
Outbuilding or garden room
Approved
May 2025
PA25/0351
16, Harvey Road, Tw4 5lu
Loft or dormer
Under consideration
–
25/0078/PS192
16, Harvey Road, Tw4 5lu
Rear extension
Under consideration
–
25/0094/PDE
435, Hanworth Road, Tw4 5lq
Rear extension
Approved
Jan 2025
24/3103/HOT
144, Waverley Avenue, Tw2 6dl
Rear extension
Refused
Jan 2025
24/3107/PDE
9, Curtis Road, Tw4 5pu
Loft or dormer
Approved
Jan 2025
24/2796/PS192
191, Powder Mill Lane, Tw2 6eq
Rear extension
Approved
Dec 2024
24/2759/HOT
435, Hanworth Road, Tw4 5lq
Two-storey extension
Refused
Nov 2024
24/2310/HOT
144, Waverley Avenue, Tw2 6dl
Rear extension
Refused
Nov 2024
24/2160/HOT
534, Hanworth Road, Tw4 5lh
Rear extension
Refused
Nov 2024
24/2127/HOT
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
–
–
83%
9 weeks
Porch or front extension
100% (5)
–
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.