House Extensions Hammersmith and Fulham
Single storey rear and double storey extensions in Hammersmith and Fulham, 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 Hammersmith and Fulham, adding space to bay-fronted Victorian and Edwardian terraces in W6, W12, W14 and SW6. We handle single and double storey, rear, side-return and wrap-around extensions from foundations to final fit-out.
In Hammersmith and Fulham, 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 Hammersmith and Fulham: 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 Hammersmith and Fulham
Hammersmith and Fulham range: choose above
Side-return extensions across Hammersmith and Fulham
The classic project on the borough's terraces is the side-return extension, filling the narrow strip of dead ground beside the rear closet wing to widen a cramped galley kitchen into a bright, open-plan kitchen-diner. Off the streets around Parsons Green and Fulham, this changes how a Victorian house lives, and we often combine it with a rear extension to create a full wrap-around footprint opening onto the garden.
We dig and pour the foundations, build the walls, install the steel beams that carry the old rear wall, and form a roof with rooflights or a glazed lantern to pull daylight deep into the plan. Groundworks near the Thames in SW6 can meet higher water tables, so we adapt the foundation design to the ground conditions we find on site.
Housing in Hammersmith and Fulham
Of the 95,080 homes the valuation list records in Hammersmith and Fulham, 56% were built before 1919, 9% between the wars and 34% since 1945; 77% are flats and 23% are houses. Where most homes are flats, a flat in Hammersmith and Fulham has no householder permitted development rights, so extending one needs planning permission and the freeholder's consent.
Trees and foundation inspections for a Hammersmith and Fulham extension
Hammersmith and Fulham has 44 conservation areas covering about half of the borough, and inside them a tree with a trunk of 75mm diameter or more cannot be worked on until six weeks' notice has been given to the council. For a rear extension that means taking out or reducing a tree that is in the way, and it can include cutting back substantial roots found in the foundation trench. That six weeks is easy to lose if nobody looks at the garden until the digger arrives. We note every tree near the footprint at the survey, including ones in the neighbour's garden, so the notice goes in while the drawings are still being finished.
Once work starts, the council's listed inspection stages set the pace of the groundworks. Foundation excavations are seen before concrete goes in, then covering of foundations, completed foundations and the damp proof course and membrane. Backfilling drain excavations is a stage of its own, and drainage inspections need 5 days' notice rather than the 1 day most visits need. On a side return, where new drains are often relaid along the extension, we book the drainage visit a week ahead so an open trench is not left waiting for an inspector.
Planning and party walls in Hammersmith and Fulham
Many rear and side-return extensions on these terraces fall under permitted development, but not all do. Corner plots, flats, side or two-storey extensions in a conservation area and anything beyond the permitted size limits need a full planning application to Hammersmith and Fulham Council. We assess your property early and tell you clearly which route applies, then coordinate the architect's drawings and the submission so you are not left guessing.
Whichever planning route you take, the structural work is signed off separately under building regulations by building control. Because you are extending against a shared boundary, party wall notices to neighbours are almost always needed on these closely spaced streets; you serve them as building owner, and we give you the drawings and programme they need. We coordinate planning, the build programme around those notices, building control and the full fit-out, including kitchen, bathroom, electrics and decoration, as one managed project.
Kitchen extensions in Hammersmith and Fulham
77% of homes in Hammersmith and Fulham are flats, and a flat has no householder permitted development, so a ground-floor flat's kitchen extension needs planning permission from Hammersmith and Fulham Council and the freeholder's consent. Most kitchen extensions here are on the 23% of homes that are houses. The fit-out is priced on its own page, kitchen renovation in Hammersmith and Fulham; the build figures are in the table above.
Double storey extensions in Hammersmith and Fulham
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 Hammersmith and Fulham often needs planning permission from Hammersmith and Fulham Council. It is a job for the 23% of homes that are houses; a flat cannot add a storey this way. Hammersmith and Fulham has 44 conservation areas covering about half of the borough, with a further two conservation areas in the north of the borough (council source). Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.
- Brickwork and mortar matched to the existing elevation
- Insulation, airtightness and thermal detailing to regulations
- Party wall process explained, and the extension built to the award
VOA Council Tax stock of properties, March 2025, for all 25 statistical areas in Hammersmith and Fulham. Counts rounded by the VOA.
Why Choose GS Renovation in Hammersmith and Fulham
GS Renovation gives Hammersmith and Fulham homeowners a single team for the whole extension, from coordinating the planning submission to foundations, steelwork and finishing. We know how the borough's terraces, closet wings and side returns behave, and we know what Hammersmith and Fulham Council expects. Our founder's 30+ years on the tools means fewer surprises and a result signed off by building control.
- Materials priced at options, so you choose the finish
- Weathertight shell reached before the fit-out begins
- Insulation and thermal detailing to current regulations
Built a new extension at rear of property. Laid foundations, drainage, raised floor, new roof and completed all fixtures and interior decoration…
George always kept to commitments and arrived on time. He offered helpful suggestions during his initial visit and promptly provided a reasonably…
It's the second time I have hired George and he has been absolutely professional and the work he did resembles perfectly what I had in mind. Being an…
FAQ
Frequently Asked Questions about House Extensions Hammersmith and Fulham
What is the going rate for house extensions around Hammersmith and Fulham?
House extensions around Hammersmith and Fulham typically costs £2,000 to £2,800 per m² for a rear extension (indicative), but scope varies more than the market does. Two Hammersmith and Fulham jobs of the same size can be different work, because the width of the opening into the house decides the steel. GS Renovation surveys and prices each on its merits at W6, with the Hammersmith and Fulham Council building control fee shown separately.
Can a Hammersmith and Fulham extension have a terrace on its roof?
Sometimes, and it is a planning question before it is a structural one. A roof terrace over a Hammersmith and Fulham extension overlooks neighbouring gardens and windows, which is the usual ground for refusal. Where it is acceptable in principle, the roof has to be designed for foot traffic, with a balustrade, a suitable finish and drainage that copes with the use.
Does an extension in Hammersmith and Fulham always need planning permission?
Not always, but the limits are easy to exceed. Some single storey rear extensions fall within permitted development, while wraparound designs combining a rear and side return generally do not, and flats have no permitted development rights at all. Building regulations approval is required either way. We establish which route applies at survey, because a design priced on the wrong assumption is the expensive kind of mistake.
Do the neighbours have to be notified about a Hammersmith and Fulham extension?
Where the work affects a shared wall or foundation, formal notice is required under the Party Wall etc. Act, and that duty falls on the owner having the work done. Excavating for foundations close to the boundary usually engages it even where the extension itself does not touch the wall. GS Renovation coordinates the build around the award and does not act as the surveyor.
What happens if a drain runs under a Hammersmith and Fulham extension?
It has to be dealt with rather than built over blind. Many rear gardens in Hammersmith and Fulham contain a shared drain, and building over or near one requires agreement from the water authority alongside building control. The options are diverting the run, or building over it with the right protection and access retained. A camera survey before the foundations are set out establishes which applies.
Can an extension in Hammersmith and Fulham be built in phases?
The shell cannot sensibly be, though the fit out can. At your Hammersmith and Fulham property the foundations, structure, roof and weathertight envelope are one continuous operation, because a partly built extension deteriorates and the house is open to weather. Once it is closed in, the internal finishes and the kitchen can follow later if that suits the budget.
Does a Hammersmith and Fulham extension near the river need a flood risk assessment?
Yes, where the extension needs planning permission and the address falls in a flood risk zone. Such zones cover two thirds of the borough, and Hammersmith and Fulham Council's guidance calls for a flood risk assessment with any application for a property inside one. Homes near the River Thames are the obvious case, but the zone reaches much further. The assessment is commissioned alongside the drawings, so the application is complete when it goes in.
Can a Hammersmith and Fulham extension go through building control on a Building Notice?
It can, but the council recommends a Building Notice only for very small works, and an extension with new foundations and steel is not that. Where a Building Notice is used for an extension, a set of structural calculations must still be submitted for all structural work. So the engineer's design is needed either way. Both routes cost exactly the same, and Full Plans simply has the design checked before the ground is broken rather than during the build.
Will a Hammersmith and Fulham rear extension be liable for the Community Infrastructure Levy?
Only where it creates a new dwelling or adds new floorspace of 100m2 or more. Those two tests set liability for CIL in Hammersmith and Fulham under the charging schedule that became effective on 1 September 2015. A single storey rear or side return extension on a terrace falls well under that size. A larger scheme, or one that adds a separate flat, is measured carefully at drawing stage, so any liability is known before the application goes in.
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