Improving at TW9 3HS

What you could build at TW9 3HS: 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 Kew Gardens, Richmond upon Thames.

61extensions seen within 600 m in the last 10 years

4loft conversions within 600 m in the last 10 years

92%of 144 householder applications nearby approved (since 2023)

106.9extensions 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.
In the Kew Gardens conservation area: permitted development is narrower (for example no side extensions or roof cladding), and demolition and works to trees need consent.
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.

What neighbours have built

Home	Work	Seen	Space added	Floor area	Rooms	Distance
10, Lichfield Road	Extension	2026	+9 m²	237 m² → 246 m²	9 → 9	127 m
50, Leyborne Park	Extension	2026	+17 m²	81 m² → 98 m²	4 → 3	242 m
350, Kew Road	Extension	2026	+15 m²	221 m² → 236 m²	10 → 10	286 m
33, West Park Road	Extension	2026	+12 m²	167 m² → 179 m²	7 → 7	430 m
28, High Park Road	Extension	2026	+48 m²	66 m² → 114 m²	–	482 m
21, Ruskin Avenue	Extension	2026	+10 m²	158 m² → 168 m²	7 → 6	505 m

Planning applications nearby

Address	Work	Outcome	Decided	Drawings and agent
11, Maze Road, Tw9 3da	Other householder work	Under consideration	–	PA26/3214
32, Ennerdale Road, Tw9 3pf	Garage conversion or garage	Under consideration	–	PA26/3283
67, Gloucester Road, Tw9 3bt	Loft or dormer	Under consideration	–	PA26/3245
37, Burlington Avenue, Tw9 4dg	Loft or dormer	Under consideration	–	PA26/2959
37, Burlington Avenue, Tw9 4dg	Rear extension	Under consideration	–	PA26/2904
18, Gloucester Road, Tw9 3bu	Other householder work	Approved	Oct 2026	PA26/2835

How often householder applications are approved

Work	Kew Gardens	Richmond upon Thames	London	Typical decision time
All householder applications	91% (284)	–	80%	8 weeks
Loft or dormer	87% (87)	–	81%	8 weeks
Rear extension	93% (59)	–	79%	8 weeks
Two-storey extension	75% (12)	–	72%	8 weeks
Other householder work	94% (31)	–	70%	8 weeks
Side return or wrap-around	100% (11)	–	88%	8 weeks
Windows, doors or cladding	96% (44)	–	90%	8 weeks
Outbuilding or garden room	89% (9)	–	79%	8 weeks
Side extension	100% (5)	–	86%	8 weeks
Garage conversion or garage	86% (14)

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 Kew Gardens.

Your home is worthExtra space you need (m²)Homes here sell for, per m²Building cost per m²Share of that an extension adds (%)

Move to a home 20 m² bigger (about £1,266,000)

Stamp duty on the new home	£70,350
Estate agent on yours 1.2% + VAT	£15,480
Solicitors, buying and selling	£3,000
Survey	£600
Removals	£1,500
Money gone	£90,930

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	−£114,600
Money gone	−£57,100

On these figures, extending loses about £148,030 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.

Find help: RIBA Find an Architect ↗ · CIAT architectural technologists ↗ · TrustMark tradespeople ↗ · Federation of Master Builders ↗ · Planning Portal guides ↗

General guidance, not planning or legal advice. Fees and rules as checked in October 2026; confirm with the council.

Energy certificates: MHCLG (OGL). Planning applications: GLA Planning London Datahub. Conservation areas and Article 4: planning.data.gov.uk (OGL).

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