House Extensions Hanwell
Single storey rear and double storey extensions in Hanwell, planning, structure and build under one contract.
- Rated 4.9 from 31 reviews on MyBuilder
- Single-storey rear extension from £40,000
- Free site survey, itemised quote
GS Renovation builds extensions throughout Hanwell, tailored to the bay-fronted Victorian and Edwardian terraces that line its streets near the river. We handle groundworks, steel, roofing and full fit-out, giving these period homes the extra ground floor space families here want.
In Hanwell, a single-storey rear extension typically starts from £40,000, or £2,000 to £2,800 per m² (indicative London ranges, Architecture for London, Resi, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Hanwell: the structural engineer we appoint designs the structure, we build it, and building control signs it off.
Price guide
| Work | Indicative London range |
|---|---|
| Single-storey rear extension | from £40,000 |
| Rear extension, per m² | £2,000 to £2,800 |
| Side return, per m² | £2,400 to £3,200 |
| Wraparound, per m² | £2,400 to £3,200 |
| Double storey, per m² | £1,800 to £2,600 |
| Basement extension | see the basement page |
Indicative London ranges (Architecture for London, Resi, MyBuilder and Checkatrade, 2026), not a quotation. Prices checked September 2026. Full breakdown: Extension Costs & Planning.
Quick estimate for Hanwell
Hanwell range: choose above
Side-return and rear extensions in Hanwell
The side return, that narrow strip of ground running alongside the rear closet wing, is the classic Hanwell extension. Filling it in widens a cramped galley kitchen into a proper open-plan kitchen-diner, usually with a steel beam replacing the old external wall and rooflights bringing daylight deep into the plan. A rear extension pushes further into the garden, and a wrap-around combines both for the biggest gain in space.
We start with the groundworks, which in Hanwell means checking for nearby trees and drainage runs and digging foundations to the depth building control requires. Then come the steel, the walls, the roof and the fit-out. Because we run the whole build with one team, the structure, the services and the finishes all come together without the gaps that happen when trades are hired piecemeal.
Housing in Hanwell
The Council Tax list puts Hanwell at about 10,370 homes, 42% flats against 58% houses; 36% went up before 1919, 34% between the wars and 30% after 1945. A rear extension on a terrace in Hanwell digs foundations close to both neighbours, so notices to both are normal, and 42% of homes here are terraced.
Extending a Hanwell house inside or outside a conservation area
Start with the map. Ealing's Hanwell conservation areas include Churchfields, Cuckoo Estate, Hanwell Cemeteries, Hanwell Clock Tower and Hanwell Village Green, and Ealing says normal permitted development rights are restricted in conservation areas. For a house inside one, a side extension or a two-storey rear extension needs a planning application, while a single-storey rear extension can still be permitted development unless an Article 4 direction says otherwise. Ealing's SPD 4 gives a benchmark: a single-storey rear extension up to 3 metres deep and 3 metres high will in most cases be acceptable. A scheme at or inside that size is the natural starting point.
On site, the order is set by what Ealing inspects. Its sample inspection plan for a single-storey extension starts at commencement and the excavations, then covers the DPC, the damp-proof membrane under the floor and the floor insulation. In a Hanwell terrace the old rear addition often has to be partly taken down first, and Ealing reminds anyone demolishing a structure that Section 80 of the Building Act 1984 requires them to notify the council. Ask building control whether your demolition is caught before the scaffold arrives, so notice does not hold up the dig.
Planning and permitted development in Ealing
Whether your Hanwell extension needs a full planning application or falls under permitted development depends on the property. Many single-storey rear extensions on unaltered terraces proceed under permitted development within the size and height limits, while double-storey work, any extension to a flat, and side extensions in a conservation area need a planning application to Ealing Council. We assess your specific house before any drawings are commissioned.
Separately from planning, every extension must meet building regulations, which govern the foundations, the steel, insulation, fire safety and drainage, and building control inspects these as the work proceeds. Where your extension touches a wall shared with a neighbouring terrace, the Party Wall Act applies too. We coordinate all three strands, planning, building control and party wall, so nothing stalls the build.
Kitchen extensions in Hanwell
72% of the houses in Hanwell are terraced. On a terrace the kitchen extension is built out from the back, into the side return where the house has one or across the full rear width, and a steel beam takes the old back wall so the kitchen and the new room become one space. The fit-out is priced on its own page, kitchen renovation in Hanwell; the build figures are in the table above.
Double storey extensions in Hanwell
Under permitted development a two-storey rear extension can go no more than 3 metres beyond the original rear wall and must stay at least 7 metres from the rear boundary, and in a conservation area it is not permitted development at all. Many gardens are too short for the 7 metre rule, so a double storey extension in Hanwell often needs planning permission from Ealing Council. On the 42% of homes that are terraced, the neighbours' windows usually decide the depth. Ealing Council's Hanwell conservation areas include Churchfields, Cuckoo Estate, Hanwell Cemeteries, Hanwell Clock Tower and Hanwell Village Green (council source). Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.
- Levels, drainage and landscaping made good around the new build
- Wrap-around extensions and infills
- Flat and pitched roofs with rooflights or lanterns
VOA Council Tax stock of properties, March 2025, for Hanwell, Elthorne Park and Cuckoo Park. Counts rounded by the VOA.
Why Hanwell Homeowners Choose GS Renovation
Hanwell homeowners choose GS Renovation because we manage the extension end to end, from the first foundation to the final coat of paint. We know which W7 terraces suit permitted development and which need an Ealing Council application, we understand the shared party walls, and we build to last. Our founder's 30+ years of extensions back the work.
- Straight advice on what is and is not worth spending money on
- Foundation depth set after trial holes, drains and trees are checked
- Garden levels and access made good where the build meets outside
Built a new extension at rear of property. Laid foundations, drainage, raised floor, new roof and completed all fixtures and interior decoration…
The kitchen has been fitted to the high standard. Saaid was polite, professional, tidy, he pays attention to a little details that make huge…
Saiid did a complete refurbishment of our small bathroom. This involved ripping out the existing bath/shower, basin, toilet, pipework, and tiles and…
FAQ
Frequently Asked Questions about House Extensions Hanwell
How does your house extensions price in Hanwell compare with a national firm's?
Against a national firm, a GS Renovation quotation for house extensions in Hanwell is more transparent: every line within £2,000 to £2,800 per m² for a rear extension (indicative) is visible, including the engineer's design and the Ealing Council building control fee. National pricing tends to be a rate per square metre for a W7 address nobody has visited, which misses that the drainage run under the footprint decides the foundations.
Will my Hanwell side-return extension need planning permission?
Many single-storey side-return and rear extensions on unaltered Hanwell terraces fall under permitted development within the size limits, so no planning application is needed. Larger, double-storey or conservation-area schemes usually require permission from Ealing Council. Either way the work must meet building regulations, and a shared party wall means a party wall notice, which you serve as building owner. We assess your house first. A listed building is the exception: work that affects its character, inside or out, including an extension or taking out a wall or chimney breast, needs listed building consent from Ealing Council, and doing it without consent is a criminal offence.
What do we do about the drain running down the side return of our Hanwell house?
It can usually be built over, but it needs a plan. The side return often carries the soil pipe from upstairs and a gully, so the extension either diverts that run or encloses it with an access chamber inside the new floor. If the drain also serves next door, it counts as a public sewer and needs the water company's consent under Part H before foundations are dug.
Will I need to tell my neighbour before digging foundations for my Hanwell extension?
In a terrace, almost certainly. Any trench within 3 metres of next door's house that goes deeper than their foundations requires one month's notice under the Party Wall etc. Act 1996. Victorian footings are often shallow, so new foundations nearly always go below them. Getting notices out early keeps the start date on track if the neighbour wants a surveyor.
How do we get daylight into the middle of a Hanwell side-return extension?
Rooflights or a glazed roof along the old side wall line. Filling the side return makes the kitchen wider but pushes the middle room further from any window, so glazing in the roof is what keeps it bright. Part L sets limits on heat loss through glass, so the glazing spec and wall insulation are balanced together. Frameless strips suit narrow returns best.
How is my Hanwell kitchen joined to the new extension?
By removing the old outside wall of the closet wing and inserting steel. Because that wall carries the rear wing's upper floor or roof, the engineer usually specifies a beam supported on posts, sometimes as a goalpost frame. The new extension is built and weathered first, and only then is the old wall taken out, so the house stays enclosed for most of the build.
Can a Hanwell extension near a public sewer go ahead on a building notice?
Not within the distance Ealing sets. Its guidance rules out a building notice for any extension, erection or underpinning built over a public sewer or within 3.0m of one, judged against the Thames Water map of sewers. A drain shared with next door usually counts as a public sewer, so check the map before the drawings are finished. The job then goes in as a full plan application, and the water company's agreement to build near the pipe is in place before the trench is dug.
Is a 30 minute planning appointment useful before designing a Hanwell extension?
It is, when the house is in a conservation area or the extension goes beyond Ealing's usual benchmark. Ealing offers a 30 minute appointment with a planner, either verbal advice only or with written advice. Bring a simple sketch with the depth and height marked, and photographs of both neighbours' rear windows. The planner's view on depth and roof form then shapes the drawings, instead of an objection arriving after the application is in.
At what floor area does a Hanwell extension move into a higher building control charge band?
At 40m2. Ealing's domestic charge table has a lower band for extensions under 40m2 and a higher one from 40m2 to 60m2. A single-storey kitchen extension on a Hanwell terrace normally falls in the lower band, while wrapping into the side return adds area and a two-storey scheme is more likely to cross the line. Work the area out from the drawings before the application goes in, so the fee is not a surprise.
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