Where in Hillingdon does a house extensions actually get determined?
Each Hillingdon postcode district we work in, what the housing there mostly is, and who validates a house extensions scheme in it. Figures in the fee column are the statutory England charges for 2026 that go to the council. Ours are separate, and agreed before a drawing is started.
| Postcode | Area | Dominant stock | What it means for a house extensions |
|---|
| UB10 | Hillingdon / Ickenham | 1930s semi-detached | A house extensions at an UB10 address in Hillingdon / Ickenham is determined by Hillingdon Council under its own Local Plan policies for Hillingdon / Ickenham. |
| UB8 | Uxbridge | Georgian fragments, 1930s semi-detached, post-war flats | Uxbridge is where the council itself sits, so an extension application from a UB8 address is validated a short walk from the house it concerns. |
| HA4 | Ruislip | 1930s semi-detached, Tudor cottages | Ruislip, in HA4, is one of the parts of the borough carrying a village conservation area, and the same officers decide extensions inside and outside that boundary. |
| HA6 | Northwood | 1930s detached, Edwardian villas | Northwood is the northern tip of the borough, on HA6, and its extension applications are read against exactly the Local Plan that applies everywhere else in Hillingdon. |
| UB3 | Hayes | 1930s semi-detached, post-war estates | Hayes sits in the south of the borough near Heathrow, and much of the housing there is post-war, which normally means generous plot depth behind a rear addition. |
| UB7 | West Drayton | 1930s semi-detached, post-war | West Drayton lies at the western edge of Hillingdon and shares the UB7 district with Yiewsley. Extension work from either goes to the same council planning team. |
| UB10 | Ickenham | 1930s semi-detached, Tudor fragments | Ickenham shares UB10 with Hillingdon village. Both send extension applications to one set of case officers, and both are judged against the same adopted design guidance. |
| UB9 | Harefield | Tudor and Georgian fragments, 1930s semi-detached | Harefield is the far north of the borough, largely ringed by Metropolitan Green Belt, and it is that designation rather than the council team that usually limits an extension there. |
| UB7 | Yiewsley | 1930s semi-detached | Yiewsley adjoins West Drayton and the two are handled as one area for casework, with proposals determined by Hillingdon under identical policies. |
| HA5 | Eastcote | 1930s semi-detached | Eastcote shares HA5 with Pinner, which is in Harrow, so an Eastcote address is confirmed against the borough boundary before the extension application is lodged. |
What changes about a house extensions in each part of Hillingdon?
Pitch, wall build-up and plot depth shift across a handful of Hillingdon streets, and every shift moves what an extension can achieve at a given address. Close to a third of the borough’s 118,250 dwellings went up in the 1930s — 29.8% of them, on the VOA stock table for 31 March 2025 — which is why so many of these projects begin with the same house and finish somewhere different.
- Hillingdon (UB10) — 1930s semi-detached, post-war defines Hillingdon, where 1930s semi-detached set what a house extensions can do. 1930s semis here have the deepest rear gardens in the area across UB10. Any Hillingdon house extensions is validated by Hillingdon Council, with Hillingdon Tube the usual Hillingdon reference point on the site plan.
- Near Hillingdon: West Drayton (UB7) — a house extensions in West Drayton starts from 1930s semi-detached, post-war, and West Drayton reads as 1930s semi-detached. 1930s semis here have the deepest rear gardens in the area in UB7. Hillingdon Council assesses West Drayton house extensions against its own West Drayton character guidance, and the location plan we draw for West Drayton references West Drayton station.
- Near Hillingdon: Ickenham (UB10) — house extensions work in Ickenham means 1930s semi-detached, tudor fragments. Ickenham is 1930s semi-detached, village conservation. 1930s semis here have the deepest rear gardens in the area throughout UB10. Hillingdon Council decides the Ickenham application, and Ickenham Village anchors the Ickenham location plan.
- Near Hillingdon: Harefield (UB9) — a house extensions in Harefield starts from tudor and georgian fragments, 1930s semi-detached, and Harefield reads as village conservation, rural fringe. Georgian rear elevations here are usually the listed or locally listed face of the building in UB9. Hillingdon Council assesses Harefield house extensions against its own Harefield character guidance, and the location plan we draw for Harefield references Harefield Hospital.
- Near Hillingdon: Yiewsley (UB7) — house extensions work in Yiewsley means 1930s semi-detached. Yiewsley is 1930s semi-detached. 1930s semis here have the deepest rear gardens in the area throughout UB7. Hillingdon Council decides the Yiewsley application, and Yiewsley High Street anchors the Yiewsley location plan.
- Near Hillingdon: Eastcote (HA5) — 1930s semi-detached defines Eastcote, where 1930s semi-detached set what a house extensions can do. 1930s semis here have the deepest rear gardens in the area across HA5. Any Eastcote house extensions is validated by Hillingdon Council, with Eastcote Tube the usual Eastcote reference point on the site plan.
- Near Hillingdon: Uxbridge (UB8) — a house extensions in Uxbridge starts from georgian fragments, 1930s semi-detached, post-war flats, and Uxbridge reads as Georgian centre, 1930s residential. Georgian rear elevations here are usually the listed or locally listed face of the building in UB8. Hillingdon Council assesses Uxbridge house extensions against its own Uxbridge character guidance, and the location plan we draw for Uxbridge references Uxbridge High Street.
What local planning policy applies to a house extensions in Hillingdon?
Conservation areas covering Hillingdon: 29 of them, and Uxbridge, Ruislip Village and Northwood are the three owners here run into most. Once an address falls inside one the fallback disappears: instead of a £249 prior approval settled in six weeks, the scheme becomes a full householder application at £548 with eight weeks to run, and an agreed extension on top of that is common in this borough. In Northwood the street elevation gets read first and the floor plan second. Conservation area status is checked before we quote.
Hillingdon permitted development status: there is no borough-wide direction from Hillingdon Council, so a house extensions at a UB10 address is normally still permitted development. We certify that with a £274 Lawful Development Certificate rather than leaving a Hillingdon sale to argue it later.
Hillingdon housing stock: 1930s semi-detached dominates; Metropolitan Green Belt covers much of north Hillingdon; Victorian cottages in Uxbridge and Ruislip villages; post-war housing near Heathrow. Largest outer west London borough; significant Green Belt; Heathrow noise contours affect planning decisions in Harmondsworth and Sipson. Read that before choosing a house extensions route in Hillingdon — construction, not postcode, sets what is achievable.
Who decides a house extensions on the edge of Hillingdon?
- Harrow — the Harrow boundary runs against Hillingdon, so a house extensions a street from Hillingdon is decided by Harrow Council instead. Harrow runs 29 conservation areas across HA1 and its neighbours, which is why house extensions priced for Hillingdon are re-checked against Harrow policy whenever the Hillingdon address sits on that edge.
- Ealing — adjoining Hillingdon, with 30 conservation areas centred on W3. A house extensions on the far side of the Hillingdon line is determined by Ealing Council, so the Hillingdon quote for house extensions is checked against Ealing guidance before it is issued.
- Hounslow — cross the Hillingdon boundary and Hounslow Council takes the house extensions instead, applying 30 conservation areas of its own around W3. We re-price house extensions at the Hillingdon edge because Hounslow policy and Hillingdon policy rarely align on house extensions depth.
Sources for this Hillingdon house extensions 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.
