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What can I build, and will it pay? The planning rules, what neighbours have built, planning decisions, energy upgrades, and whether extending pays.
| Syon Green | Hounslow | England and Wales | |
|---|---|---|---|
| Postcodes in a conservation area | 14% | 18% | 10% |
| Postcodes under an Article 4 direction | 98% | 97% | 16% |
| Listed buildings | 30 | 7 | 12 |
| Postcodes in a tree preservation order zone | 0% | 0% | 3% |
| Flats | 48% | 44% | 22% |
| Building | Grade | Distance |
|---|---|---|
| 200, Linkfield Road | II | 120 m |
| 202 and 204, Linkfield Road | II | 140 m |
| 173, Twickenham Road | II | 170 m |
| 185 and 187, Twickenham Road | II | 200 m |
| Sarah Sermons Almshouses | II | 340 m |
| 92-96, Twickenham Road | II | 380 m |
| the Parsonage | II | 390 m |
| Thanet House | II | 400 m |
| Sundial at Gumley House | II | 420 m |
| Church of St John | II | 430 m |
| Gumley House Gumley House (Convent) | II* | 430 m |
| St Johns Cottage | II | 440 m |
Nearest 12 shown. Grade I and II* are the most important few per cent. Listing means consent is needed for most changes, inside and out. Contains Historic England data © Historic England 2026 (via planning.data.gov.uk), OGL.
planning.data.gov.uk (OGL), Historic England. The rules at one address are on its postcode's Improving page. General guidance, not planning advice.
| Home | Work | Seen | Space added | Rooms |
|---|---|---|---|---|
| 27, Mill Plat Avenue | Extension | 2026 | +9 m² | 3 → 4 |
| 409, London Road | Extension | 2026 | +103 m² | 8 → 6 |
| 18, Linkfield Road | Extension | 2026 | +39 m² | – |
| 20, Newton Road | Extension | 2026 | +67 m² | – |
| 49, Clydesdale Close | Extension | 2026 | +39 m² | 3 → 4 |
| 5, Loring Road | Extension | 2026 | +8 m² | 4 → 3 |
| 12, Hartland Road | Extension | 2026 | +24 m² | – |
| 93, Hartham Road | Extension | 2026 | +27 m² | – |
| 6, Teesdale Gardens | Extension | 2026 | +29 m² | 4 → 5 |
| 14, Wood Lane | Extension | 2026 | +55 m² | 4 → 4 |
| Work | Syon Green | Hounslow | London |
|---|---|---|---|
| All householder applications | 71% (146) | 74% (5222) | 80% |
| Loft or dormer | 84% (37) | 80% (1326) | 81% |
| Other householder work | 60% (15) | 51% (350) | 70% |
| Outbuilding or garden room | 50% (8) | 65% (452) | 79% |
| Rear extension | 67% (54) | 76% (1756) | 79% |
| Side return or wrap-around | 83% (12) | 84% (243) | 88% |
| Two-storey extension | 67% (12) | 67% (570) | 72% |
| Windows, doors or cladding | 80% (5) | 85% (135) | 90% |
| Basement | – | 73% (82) | 83% |
| Porch or front extension | – | 55% (74) | 81% |
| Garage conversion or garage | – | 78% (107) | 88% |
| Side extension | – | 69% (127) | 86% |
Householder applications decided since 2023 (number decided in brackets); withdrawn ones aren't counted. GLA Planning London Datahub.
| Syon Green | Hounslow | England and Wales | |
|---|---|---|---|
| Rated A or B | 20% | 12% | 12% |
| Rated E, F or G | 11% | 12% | 16% |
| Homes on mains gas | 76% | 79% | 86% |
| Gas use per home (kWh a year) | 10,296 | 12,470 | 11,043 |
| Households in fuel poverty | 9% | 10% | 10% |
| Homes built before 1919 | 20% | 15% | 20% |
A home's own recommended upgrades and their costs are on its energy certificate, shown on its page.
MHCLG energy certificates; DESNZ fuel poverty.
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); in London, 15.1% (15,951 resales).
Rough build costs and resale evidence, not quotes or a valuation. How extensions pay off by size, type and region.
The money you don't get back either way, for the same extra space in Syon Green.
| Stamp duty on the new home | £19,000 |
|---|---|
| Estate agent on yours 1.2% + VAT | £6,624 |
| Solicitors, buying and selling | £3,000 |
| Survey | £600 |
| Removals | £1,500 |
| Money gone | £30,724 |
| Building, plus 15% for design, planning and contingency | £57,500 |
|---|---|
| Less what it adds to your home's value 60% of the local price | −£72,000 |
| Money gone | −£14,500 |
On these figures, extending loses about £45,224 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.
Where people extend most, and where the planning rules are tighter.
| Hounslow Meadows | 48.7 | 0% | 100% | 6 | 7% |
|---|---|---|---|---|---|
| Chiswick North East | 47.7 | 47% | 99% | 118 | 13% |
| Chiswick South East | 47.7 | 60% | 95% | 63 | 4% |
| Heston West | 46.3 | 0% | 98% | 0 | 2% |
| Hounslow East | 45.8 | 0% | 98% | 2 | 2% |
| Hounslow West | 41.4 | 4% | 100% | 2 | 8% |
| Osterley & Lampton East | 40.2 | 19% | 98% | 5 | 5% |
| Heston Central & Lampton West | 37.5 | 4% | 99% | 5 | 14% |
| Cranford | 37.2 | 20% | 95% | 2 | 5% |
| Hanworth North | 34.0 | 1% | 97% | 4 | 4% |
| Heston North | 32.8 | 16% | 99% | 1 | 15% |
| North Hyde & North Cranford | 32.5 | 0% | 81% | 5 | 8% |
| Hounslow Heath | 31.5 | 4% | 97% | 9 | 3% |
| Syon Green (this one) | 30.8 | 14% | 98% | 30 | 20% |
| Brentford West & Osterley Park | 30.7 | 58% | 94% | 24 | 8% |
| Lower Feltham | 29.6 | 5% | 98% | 2 | 6% |
| Isleworth & Ivybridge | 29.2 | 42% | 95% | 27 | 16% |
| Chiswick South West | 27.9 | 68% | 98% | 38 | 3% |
| Brentford Central | 26.5 | 31% | 97% | 54 | 33% |
| Feltham East | 26.3 | 10% | 97% | 1 | 6% |
| Hanworth South | 25.5 | 5% | 98% | 14 | 2% |
| Spring Grove | 25.2 | 21% | 97% | 7 | 23% |
| Chiswick Park | 24.9 | 63% | 99% | 28 | 14% |
| Bedfont | 23.6 | 21% | 97% | 16 | 7% |
| North Feltham & Hatton | 23.5 | 0% | 95% | 6 | 5% |
| Brentford East | 21.5 | 11% | 99% | 8 | 38% |
| Feltham Central | 14.3 | 7% | 100% | 9 | 16% |
| Hounslow High Street | 12.7 | 4% | 100% | 2 | 21% |
| Kew Bridge & Gunnersbury Park | 12.1 | 21% | 96% | 20 | 55% |
| Extension |
| 2026 |
| +25 m² |
| – |
| 41, Wood Lane | Extension | 2026 | +50 m² | 6 → 5 |
|---|
| 16, Campion Road | Extension | 2026 | +66 m² | 6 → 6 |
|---|
| 52, Church Street | Extension | 2026 | +144 m² | 5 → 7 |
|---|
| 9, Parkwood Road | Extension | 2026 | +61 m² | 5 → 8 |
|---|
| 6, Church Street | Extension | 2026 | +51 m² | – |
|---|
| 33, Algar Road | Extension | 2026 | +18 m² | 6 → 6 |
|---|
| 83, College Road | Extension | 2026 | +22 m² | – |
|---|
| 40, Amhurst Gardens | Extension | 2025 | +37 m² | – |
|---|
| 50, Amhurst Gardens | Loft conversion | 2025 | +11 m² | 6 → 6 |
|---|
| 104, Linkfield Road | Extension | 2025 | +10 m² | 3 → 3 |
|---|
| 65, Castle Road | Extension | 2025 | +26 m² | – |
|---|
| 29, Castle Road | Extension | 2025 | +21 m² | – |
|---|
| 47, Linkfield Road | Extension | 2025 | +57 m² | – |
|---|
| 153, Twickenham Road | Extension | 2025 | +36 m² | – |
|---|
| 40, Newton Road | Extension | 2025 | +48 m² | 4 → 4 |
|---|
| 139, Hartham Road | Extension | 2025 | +20 m² | 3 → 5 |
|---|
| 48, Loring Road | Extension | 2025 | +37 m² | 6 → 6 |
|---|
| 27, Teesdale Gardens | Extension | 2025 | +30 m² | – |
|---|
| 27, Teesdale Gardens | Loft conversion | 2025 | +30 m² | 8 → 8 |
|---|
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.
From energy certificates: an extension where a later certificate shows more floor space, a loft conversion where roof rooms appear.
Sort by any column; open a neighbourhood for the same view.
| Neighbourhood | Council | England and Wales | |
|---|---|---|---|
| Homes with solar panels | 0.3% | 0.4% | 1.2% |
| Heated by a heat pump | 0.3% | 0.6% | 1.0% |
| Mains gas | 67.5% | 74.4% | 84.0% |
| Oil or LPG | 0.0% | 0.1% | 4.1% |
| Electric heating | 14.3% | 13.5% | 8.3% |
| Community heating | 17.8% | 11.3% | 2.1% |
From each home's latest energy certificate, so panels or heat pumps fitted since aren't counted and the shares are lower than today's real figures. Compare areas in the data explorer.