House Extensions Fulham
Single storey rear and double storey extensions in 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 Fulham, working with the bay-fronted Victorian and Edwardian terraces of SW6. We handle everything from a side-return infill near Parsons Green to a full wrap-around near Bishops Park, managing foundations, steel, roof and fit-out under one roof.
In 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 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 Fulham
Fulham range: choose above
Side-return and rear extensions in Fulham
A common Fulham extension is the side-return infill, filling the narrow alley beside the rear closet wing to widen a cramped galley kitchen into a bright kitchen-diner. On wider plots we add a full-width rear extension, and on some SW6 corner and end-of-terrace houses a wrap-around that combines both. Each needs new foundations, steel beams over the openings and a carefully detailed roof, often with rooflights to bring daylight deep into the plan.
We start with the groundworks and foundations, checking for drains and the shared boundary before we dig, then build up in brick or blockwork to match the existing house. The old rear wall usually comes out on a steel, tying the new space to the original reception rooms. We finish with insulation, glazing, plastering and the full internal fit-out so the extension is ready to use.
Housing in Fulham
Fulham's housing, as the Council Tax list records it, is about 24,310 homes: 24% houses, 76% flats, with 58% pre-1919, 4% interwar and 39% built since 1945. A flat in Fulham has no householder permitted development rights, so extending one needs planning permission and the freeholder's consent, which matters here because most homes are flats.
Flood risk and floor area checks for a Fulham extension
Two thirds of Hammersmith and Fulham is within a flood risk zone, and a flood risk assessment is requested with an application for a property in one. Where a Fulham rear extension needs planning permission, that assessment matters. It can set the finished floor level of the new room, the threshold at the garden doors and whether the new drainage needs a non-return valve. Commission it before the architect fixes the floor level, because raising the extension floor later means a step down into the kitchen or a ramp nobody wanted.
Floor area is the second number to watch. Developments that add 100m2 or more of new floorspace or create a new dwelling are liable for CIL in Hammersmith and Fulham. A single-storey Fulham extension will normally sit well under that, but a wrap-around extension combined with a new lower level can approach it. Measure the gross internal area of everything being added before the planning drawings are frozen, so the liability question is settled at design stage. Relief for extending your own home exists, but it has to be claimed before work starts.
Planning and party walls in Hammersmith and Fulham
Whether your Fulham extension is permitted development or needs a full planning application depends on the property. Many single-storey rear extensions fall under permitted development, but if your home has been extended before, or you want a larger or double-storey build or a side extension in a conservation area, you will need permission from Hammersmith and Fulham Council. We assess your specific house before design so you know which route applies.
Separate from planning, every extension must meet building regulations, and building control inspects the foundations, steel, insulation and drainage as the work proceeds. Because SW6 terraces share boundaries, extensions along or near the party wall trigger Party Wall Act notices, which you serve as building owner or through your surveyor. We coordinate the planning route and the building control inspections, and give you the drawings the notices need, so nothing stalls the programme.
Kitchen extensions in Fulham
76% of homes in 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 24% of homes that are houses. The fit-out is priced on its own page, kitchen renovation in Fulham; the build figures are in the table above.
Double storey extensions in 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 Fulham often needs planning permission from Hammersmith and Fulham Council. It is a job for the 24% of homes that are houses; a flat cannot add a storey this way. The council's list of property-specific Article 4 Directions includes Central Fulham (1) and Central Fulham (2) (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
- Planning applications and permitted development assessments
VOA Council Tax stock of properties, March 2025, for all 6 statistical areas in Fulham. Counts rounded by the VOA.
Why Fulham Homeowners Choose GS Renovation
Fulham homeowners choose GS Renovation because one team takes the extension from foundations to final decoration. We know the SW6 terrace, its closet wing, its side return and its shared boundaries, and we manage the council planning route and building control together. With our founder's 30+ years on the tools, we deliver tidy, structurally sound extensions that work for the way you live.
- Paperwork and certificates handed over for when you sell
- Foundation depth set after trial holes, drains and trees are checked
- Permitted development checked before you pay for a planning application
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 Fulham
How accurate is a house extensions quote for a Fulham house?
The accuracy of a house extensions quote in Fulham depends on the information behind it. A phone figure will move; one written after GS Renovation has checked the SW6 property usually does not, because the drainage run under the footprint decides the foundations, and that is only visible on site. The Hammersmith and Fulham Council building control fee is shown separately, and the range to compare against is £2,000 to £2,800 per m² for a rear extension (indicative).
Will my Fulham side-return extension need planning permission?
Many single-storey side-return and rear extensions in Fulham are permitted development, but if your terrace has already been extended, or you want a larger footprint or a side-return infill in a conservation area, you will need a planning application to Hammersmith and Fulham Council. Either way the build must meet building regulations, and we confirm the right route before design begins.
Why do drains matter for a side-return extension on a Fulham house?
Because on a Fulham house the underground pipe often runs along that side strip, exactly where the new slab will sit. A run serving your house alone can be rerouted or bridged with access kept, provided the gradients still satisfy Part H. If it proves to be a public sewer, the water company must consent before building over it, so a camera survey happens at design stage.
Which neighbour notices does an extension on a Fulham house involve?
Two are common in a terrace. The footings trigger one: if the trench lies within 3 metres of the adjoining house and goes deeper than its foundations, a notice must go out a month before digging. The steel triggers the other, since pocketing the beam into the shared wall is party structure work needing two months' warning. If either notice is dissented from, appointed surveyors settle an award before work proceeds.
Does extending a Fulham house bring energy rules to the existing rooms?
Partly. The extension itself has to meet current Part L standards for its walls, floor, roof and glazing. Any wall, floor or roof of the original house that you renovate at the same time must also be brought up to current insulation standards, so a new floor laid through into the old kitchen counts. A large expanse of glazing across the back has to be balanced elsewhere in the design.
Can we keep using the kitchen while a Fulham house extension is built?
Yes, until the late stage. While the builders work outside on footings, masonry and the new roof, the original rear wall still closes the house, so cooking carries on as normal. The disruption arrives when that wall is broken through for the steel; from then until the new room is joined up, we move a sink, fridge and worktop into the front room for you.
What structural information does a Building Notice for a Fulham extension need?
A full set of calculations. Under a Building Notice application for extensions, a set of structural calculations must be submitted for all structural work. That means the engineer's design for the foundations, the steel into the house and the roof has to exist before that work is built, whichever route you choose. With the calculations prepared anyway, a Full Plans application costs the same and has the design checked before work starts.
Does a tree in a Fulham garden affect an extension in a conservation area?
It can affect both the timing and the foundations. Works to a tree in a conservation area with a trunk diameter of 75mm or more need six weeks' notice to the council. Pruning roots or crown to make room for the extension can fall under that, so the notice goes in six weeks before the excavation date. The engineer also sizes the foundation depth for the tree, which may mean a deeper trench.
Will a Fulham extension application need a design and access statement?
Only in limited cases. In conservation areas, one is required for applications for one or more dwellings or 100 square metres or more of floor space, and for major and listed building consent applications everywhere. A single-storey rear extension to a house is usually below that threshold. A clear set of existing and proposed drawings with photographs of the rear elevation does the persuading instead.
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