Kitchen extensions · South & West London
Kitchen extensions in London: a ground floor extension with one job
We build kitchen extensions across south and west London, using side return and rear extensions to create connected kitchen, dining and living space. We plan the layout, daylight, structure and services together before construction.
The room decides the kitchen, not the other way round — which is why the kitchen has to be designed before the steel is ordered, not after the walls are up.
What you are actually buying
Nearly every ground floor extension we build is, in practice, a kitchen extension. It is the reason people extend: the existing kitchen is a narrow galley at the back of the house, disconnected from where the family actually is, and no amount of new units fixes a bad shape.
What you are buying is not more kitchen. It is a different shape of room. That distinction matters more than any other decision on this page, and it is the one most often skipped over in favour of choosing worktops.
An island needs width, not length
The single most common brief we receive is an island. The single most common reason an island does not work is that the room was extended in the wrong direction.
Extending straight out into the garden makes a room deeper. Infilling the side return makes it wider. An island needs clear space on both sides to be usable, so width is what buys it — which is why a side return infill often delivers a better kitchen than a rear extension that adds more floor area.
On a side infill in SW18 the entire point of taking in the dead alley beside the outrigger was to get an island into the middle of the room rather than pressed against a wall. The floor area gained was modest. The kitchen was transformed.
Depth still has its place. On a wider plot, or where the garden can spare it, going out is the right answer — but it should be a decision about the shape you want to cook in, not a default because the garden is the obvious direction to build.
The daylight problem is geometric, and it has three answers
A kitchen at the back of a deep London terrace has a daylight problem by geometry rather than by design. Three things fix it, and the best kitchens use all three: rooflights above the working area, a large glazed opening at the rear, and where possible a borrowed opening into the middle of the plan.
On a semi in Croydon we set an internal window above the door into the hallway, borrowing light from the new extension and pushing it into the centre of the house — the part a rear extension makes darker and the part nobody photographs. It is the cheapest move on that project and the one worth copying.
Slim-framed crittall-style doors get more glass into the same opening than a chunkier system, which is why they appear on several of our projects. If you want a single opening across the full width of the house, say so early. It changes the structural design, because the beam spanning that opening has considerably more work to do, and adding it after the steel has been specified means specifying the steel again.
Design the kitchen before the steel is ordered
This is the part that goes wrong most often, and it is entirely avoidable.
Drainage sets the sink. Waste has to run to the existing stack with adequate fall. That constraint decides where a sink and dishwasher can sensibly go, long before anyone picks a worktop.
Extraction needs a route. An island hob means running extraction through the floor or the ceiling. Decided early it is invisible. Decided late it is a boxed-in bulkhead over the middle of your new room.
Underfloor heating goes in before the slab. It is one of very few things that genuinely cannot be added afterwards without starting the floor again.
Sockets follow the layout. First fix happens well before a kitchen is fitted, so the kitchen layout has to exist by then.
A builder who asks for your kitchen drawings before ordering steel is not being difficult. They are trying to stop you paying twice.
Finishes worth considering
From projects we have completed: porcelain tile made to look like floorboards takes underfloor heating far better than timber, does not move with humidity, and survives what gets walked in from a garden. Underfloor heating is slow to respond by nature, so it rewards a learning thermostat over a switch somebody has to remember.
Exposed structure is worth raising early if you like it. On a side return in SW17 the brick was left exposed and the steel left visible rather than everything being boarded and plastered, which costs less than covering it up — but only when the decision is made at drawing stage, because steel that will be seen is specified, finished and fire-protected differently from steel that disappears.
Planning is the same as any ground floor extension
Because a kitchen extension is a ground floor extension, the same rules apply. Many single-storey rear extensions fall under permitted development, with tighter rules for flats, conservation areas and listed buildings. Anything larger, or a wraparound, usually needs a full application through your borough.
The routes can be combined. On a house in SW18 we took what permitted development allowed at the rear and applied for planning on the side, which produced a better result than either route allowed alone. Building regulations approval is required either way, and a party wall agreement if you are building at a shared boundary — a process with statutory notice periods that belongs in the programme from the beginning rather than being discovered midway.
If you own a ground floor flat rather than a house, the position is different again: flats do not have permitted development rights for extensions, and your lease will almost certainly require the freeholder's consent, which runs to its own timetable.
Common questions about kitchen extensions in London
What is the difference between a kitchen extension and a rear extension?
Structurally, nothing. A kitchen extension is a ground floor extension that happens to have a kitchen in it. The difference is the order of the decisions: the units, the island and the services are settled before the structure is priced, so the steel, the drainage and the sockets end up placed for the kitchen you are actually having.
Do I need planning permission for a kitchen extension?
Usually not, if it is a single storey rear or side return extension within permitted development limits and the house still holds those rights. A conservation area or an Article 4 direction removes them, and a flat never had them. We check the address before anything is drawn.
Can I have an island in a side return kitchen?
It is decided by width, not length. An island needs walking room on the sides you use, and a side return extension adds width exactly where that matters. Whether yours works is a question we can answer from the measurements taken at survey, before anything is designed around it.
When should I choose the kitchen itself?
Before the steel is ordered. The position of the island, the sink and the extractor decides where drainage, power and ductwork have to run, and those get set into the floor and the walls early. Choosing the kitchen late is the most common reason a finished extension ends up with a socket in the wrong place.
How do you get daylight into a side return kitchen?
Three ways, usually together: rooflights over the new section, glazing in the rear wall, and keeping the opening between the old and new parts of the room as wide as the structure allows. The geometry matters more than the area of glass, because light arriving from above reaches further into a deep room than light from the back wall.
See the work in real homes
Side and rear ground floor extensionView the project →
Ground floor wraparound extensionView the project →
Bring your kitchen ideas, however rough
Book a free site survey. We will look at the drainage, the light and the shape of what you have, then tell you whether the room you need comes from going out, going sideways, or both.
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From the portfolio
Kitchens opened up on the ground floor
Wandsworth, SW17 · Side returnGround floor side return infillThe owners asked us not to cover the steel up. They were right.
Wandsworth, SW18 · Side extensionGround floor side extensionThe dead alley down the side became the middle of the kitchen.
Merton, SM4 · WraparoundGround floor wraparound extensionOne trip round the back, rather than two jobs a few years apart.