Which Hounslow postcodes does this permitted development scheme service cover?
Hounslow refuses more householder applications than almost any London borough, and it loses an unusual share of those refusals on appeal. The council approved 69.9% of the 2,310 householder applications it decided in the three years to March 2026, second lowest of the 32 boroughs the figure can be calculated for, against 83.0% across London. Of the 659 Hounslow householder appeals the Planning Inspectorate decided between 2016 and 2026, it allowed 325 — 49.3%, against 35.6% across England (MHCLG planning application statistics and Planning Inspectorate appeal casework, both retrieved 1 September 2026). Roughly half of what this borough refuses does not survive review. The table lists the districts we draw in; fees quoted are the statutory England rates for 2026.
| Postcode | Area | Dominant stock | What it means for a permitted development scheme |
|---|
| TW8 | Brentford | Georgian fragments, Victorian terraces, new-build | Brentford is Hounslow's throughout. Flood Zone 3 covers 9.74% of the borough's 55.96 square kilometres, and it clusters on the low ground beside the Thames and the Brent that TW8 occupies. Permitted development itself is unaffected by that; any part of a scheme that does need an application will carry a Flood Risk Assessment with it. |
| TW13 | Feltham | 1930s semi-detached, post-war estates | Feltham is wholly within Hounslow. The 1930s semi-detached stock that accounts for 20.2% of the borough's homes at 31 March 2025 is well represented here, and those plots are usually deep enough to reach 6m at the back, which is the point the neighbour consultation procedure starts rather than a straightforward certificate. |
| TW14 | Feltham / East Bedfont | Edwardian villas in Chiswick and Turnham Green; Georgian in Isleworth; 1930s semi-detached in Hounslow and Feltham; riverside new-build in Brentford | A permitted development scheme at an TW14 address in Feltham / East Bedfont is determined by Hounslow Council under its own Local Plan policies for Feltham / East Bedfont. |
| W3 | Acton | Victorian and Edwardian terraces | Acton is predominantly Ealing's, with a fringe of W3 in Hounslow. Ealing refused 243 of the 891 larger-extension prior approvals it determined over the three years to March 2026; Hounslow refused 215 of 741. Similar odds, different case officers, and the address rather than the postcode decides which set applies. Source: MHCLG live planning statistics. |
| W4 | Chiswick / Bedford Park | Arts & Crafts villas (listed) | W4 is split. Most Chiswick and Bedford Park addresses are Hounslow's, but a strip along the northern edge falls to Ealing, and the two authorities do not reach identical conclusions on the same 6m rear extension. Establish which one validates your address before the drawings are prepared, not after they are refused. |
| TW3 | Hounslow | 1930s semi-detached, post-war flats | The town centre sits inside its own borough, so TW3 raises no boundary question at all. Density is the constraint instead. Back gardens on the terraces around the High Street are short, and a rear extension that would go unremarked on a Feltham plot can fail the impact test on adjoining occupiers here. |
| TW4 | Hounslow West | Edwardian villas in Chiswick and Turnham Green; Georgian in Isleworth; 1930s semi-detached in Hounslow and Feltham; riverside new-build in Brentford | TW4 is a single-authority postcode: everything in Hounslow West is validated by the borough. Before committing to a 6m extension here, the figure that matters is Hounslow's own refusal count, 215 out of 741 determined, set against a refused share of a quarter across London as a whole. |
| TW5 | Heston / Cranford | Edwardian villas in Chiswick and Turnham Green; Georgian in Isleworth; 1930s semi-detached in Hounslow and Feltham; riverside new-build in Brentford | Heston and Cranford lie entirely inside the borough, so a TW5 prior approval or certificate goes to Hounslow and to no one else. The housing here is mostly inter-war and post-war semi-detached on deep plots, which is the geometry the larger rear extension route was written for. |
Which Hounslow neighbourhoods suit a permitted development scheme best?
Read together those two figures say something practical: here a refusal is not the end of the process, and a scheme that genuinely complies with policy is worth defending rather than immediately redesigning. The borough is also two places joined at Brentford. Chiswick, Turnham Green and Isleworth are thick with designation and statutory listing — Hounslow holds 519 listed buildings, 32 of them Grade I (Historic England, via the MHCLG Planning Data Platform, retrieved 2 September 2026). Feltham, Hanworth and Hounslow itself are interwar suburb, with 20.2% of the borough’s 111,270 dwellings built in the 1930s (VOA council tax stock at 31 March 2025, published via the London Datastore).
- Chiswick and Turnham Green (W4) — Edwardian villas and Victorian terraces, and the heaviest designation in the borough. Inside a conservation area the house stands on article 2(3) land, which removes side extensions, rear extensions of more than one storey, cladding and Class B roof enlargements together. A rear dormer that would be lawful in Feltham needs a full householder application here.
- Isleworth and the riverside (TW7, TW8) — Georgian and early Victorian fabric beside some of the largest designations in west London: Osterley Park covers 284.5 hectares and Isleworth Riverside 154.6 (planning.data.gov.uk conservation area register, retrieved 1 September 2026). On Georgian stock the first question is not the conservation area at all but whether the building is listed, because listed building consent covers interiors as well as elevations, is a separate application from planning permission, and proceeding without it is a criminal matter.
- Gunnersbury and the park fringe (W4, TW8) — worth singling out because the register carries an article 4 direction attached to the Gunnersbury Park designation. Where a direction and a conservation area overlap they withdraw different rights, and both have to be read: neither one implies the other, and a heritage statement answering only one of them answers half the case.
- Hounslow, Feltham and Hanworth (TW3, TW13) — interwar semis with side passages and deep rear gardens, and the part of the borough where permitted development still does most of the work. Semi-detached rather than terraced means a 50 cubic metre loft allowance instead of 40, and a hip-to-gable is routine rather than exceptional.
- Deep rear extensions, borough-wide — one number to check before drawing. Hounslow determined 741 larger householder prior approvals in three years: 448 needed none, 78 were granted, 215 were refused. That is a 29.0% refusal share against 24.9% pooled across London (MHCLG planning application statistics, PS1, retrieved 1 September 2026).
Does Hounslow planning policy restrict a permitted development scheme?
What a designation costs you here. Inside a Hounslow conservation area the permitted development route closes and a £548 householder application takes the place of the £274 certificate or the £249 prior approval. Bedford Park, Old Isleworth, Brentford and the Chiswick streets are where owners meet this most often, and on those the front elevation is assessed before anything behind it is looked at.
There is no borough-wide direction against ordinary householder work. Outside the designated areas, an extension or a loft in Hounslow is governed by the national rules and nothing else. We still certify it with a £274 Lawful Development Certificate rather than leaving a conveyancing solicitor to argue the point in ten years’ time; the borough recorded 1,352 such applications in the three years to March 2026 (MHCLG planning application statistics, PS1, retrieved 1 September 2026), and the return carries no granted-or-refused split, so that figure describes use of the route rather than success in it.
Where Hounslow really is hard, and it is not extensions. Change of use. The council approved 51 of the 173 change-of-use applications it decided, 29.5%, the lowest rate of the 32 boroughs for which the figure can be computed and less than half the London figure of 59.3%. Householder work is a different proposition, and given the appeal record above, a refusal on a compliant extension here is worth testing rather than accepting.
Who decides a permitted development scheme on the edge of Hounslow?
- Ealing — the northern boundary, running through Northfields and Boston Manor, and the comparison that matters most. Ealing approved 86.6% of its householder applications over the same three years against Hounslow’s 69.9% (MHCLG planning application statistics, twelve quarters to March 2026, retrieved 1 September 2026). Nearly seventeen points between two adjoining outer-west boroughs is the strongest possible argument for confirming which council determines your address before a line is drawn.
- Richmond upon Thames — across the river from Isleworth and Brentford, and a considerably more heritage-constrained authority. What passes without comment in Feltham is no guide at all to what passes in Twickenham or Kew.
- Hammersmith and Fulham — the eastern edge at Chiswick. Different council, different appeal record, and a conservation area boundary does not carry across the borough line just because the terraces do.
- Hillingdon — the north-western edge beyond Heathrow. Airport safeguarding and public safety zones apply to parts of both boroughs and sit alongside planning policy rather than inside it, so they are checked against the specific address rather than the postcode district.
Sources for this Hounslow permitted development scheme page: borough policies maps and
conservation-area registers (2025–26), Royal Mail postcode district boundaries,
the Town and Country Planning (Fees for Applications) (England) Regulations, the Town
and Country Planning (General Permitted Development) (England) Order 2015 as amended,
and the Party Wall etc. Act 1996.
