What you could build at TW1 3EL: 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 St Margarets, Richmond upon Thames.
189extensions seen within 600 m in the last 10 years
19loft conversions within 600 m in the last 10 years
121.7extensions 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 St Margarets.
Move to a home 20 m² bigger (about £1,259,000)
Stamp duty on the new home
£69,650
Estate agent on yours 1.2% + VAT
£15,480
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£90,230
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
−£110,400
Money gone
−£52,900
On these figures, extending loses about £143,130 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.
PA26/2798
116, Amyand Park Road, Tw1 3hp
Basement
Other
Sept 2026
PA26/2825
30, The Avenue, Tw1 1ry
Loft or dormer
Approved
Oct 2026
PA26/2671
25, Lebanon Park, Tw1 3df
Loft or dormer
Approved
Sept 2026
PA26/1729
54, Richmond Road, Tw1 3be
Other householder work
Approved
Sept 2026
PA26/2209
57, Hartington Road, Tw1 3el
Side extension
Under consideration
–
PA26/2580
13, Orchard Road, Tw1 1lx
Rear extension
Approved
Sept 2026
PA26/2588
1, Broadway Avenue, Tw1 1rh
Loft or dormer
Approved
Sept 2026
PA26/2450
11, Beaconsfield Road, Tw1 3hx
Rear extension
Approved
Aug 2026
PA26/2345
10, Marble Hill Close, Tw1 3ay
Rear extension
Approved
Jul 2026
PA26/2177
5, 5 Flat 5, Riverdale Road, Tw1 2bt
Outbuilding or garden room
Approved
Jul 2026
PA26/1552
3, Strafford Road, Tw1 3ad
Loft or dormer
Approved
Sept 2026
PA26/1479
The Garden Cottage, Orleans Road, Tw1 3bj
Windows, doors or cladding
Approved
Jul 2026
PA26/0957
22, St Margarets Grove, Tw1 1jg
Two-storey extension
Under consideration
–
PA26/1556
The Garden Cottage, Orleans Road, Tw1 3bj
Rear extension
Other
Jul 2026
PA26/1613
33, Sandycoombe Road, Tw1 2lr
Loft or dormer
Under consideration
–
PA26/1567
45, Orchard Road, Tw1 1lx
Loft or dormer
Under consideration
–
PA26/1349
15, Baronsfield Road, Tw1 2qt
Side extension
Under consideration
–
PA26/1221
73, Winchester Road, Tw1 1le
Other householder work
Approved
May 2026
PA26/1043
11, Ravensbourne Road, Tw1 2dg
Loft or dormer
Other
May 2026
PA26/1063
307, Richmond Road, Tw1 2np
Loft or dormer
Approved
May 2026
PA26/0697
46, Cole Park Road, Tw1 1hs
Loft or dormer
Approved
Apr 2026
PA26/0623
8, Montpelier Row, Tw1 2nq
Basement
Under consideration
–
PA26/0338
31, South Western Road, Tw1 1lg
Rear extension
Approved
Apr 2026
PA26/0492
185, Amyand Park Road, Tw1 3hn
Loft or dormer
Approved
Mar 2026
PA26/0464
9, Riverdale Road, Tw1 2bt
Other householder work
Approved
Mar 2026
PA25/4321
25, South Western Road, Tw1 1lg
Loft or dormer
Approved
Mar 2026
PA26/0335
33, Sandycoombe Road, Tw1 2lr
Loft or dormer
Other
Feb 2026
PA25/3978
13, Lancaster Place, Tw1 1hr
Loft or dormer
Approved
Apr 2026
PA26/0049
9, Claremont Road, Tw1 2qx
Rear extension
Approved
Feb 2026
PA25/4525
21, The Avenue, Tw1 1qp
Windows, doors or cladding
Approved
Feb 2026
PA25/4518
8, Ellesmere Road, Tw1 2dl
Loft or dormer
Under consideration
–
PA25/4502
11, Ravensbourne Road, Tw1 2dg
Loft or dormer
Other
Feb 2026
PA25/4447
6, Norman Avenue, Tw1 2ly
Loft or dormer
Approved
Mar 2026
PA25/4416
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
–
–
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.