Single-Storey Rear Extension: Kitchen-Diner Layouts That Work

The single-storey rear extension is one of the most popular home improvements in the UK, and most often it becomes a kitchen-diner: a bright, open room across the back of the house, opening onto the garden. Getting that room right depends less on the finishes and more on the layout, and the layout depends on the depth of the extension.

Here are the layouts that work, the depth each one needs, and the traps to avoid.

First, the depth question

Under permitted development, a single-storey rear extension can usually project up to 3 metres from the original rear wall of a semi-detached or terraced house, and 4 metres for a detached house. The larger home extension route, with prior approval from the council, allows up to 6 metres and 8 metres respectively. Our permitted development guide explains the conditions.

Those few metres decide what fits. Remember the extension usually joins an existing room, so the usable space is the new depth plus whatever you open up from the original house.

Layout 1: kitchen along the side wall, dining by the doors

The kitchen runs along one side wall, with an island parallel to it, and the dining table sits at the garden end beside the glazing.

Works with: around 3 metres of new depth plus an opened-up back room
Why it works: the cook faces into the room and the garden, the table gets the best light, and the route to the garden doors stays clear
Watch for: the island clearance. You need around 1000 to 1200 mm between the island and the kitchen run

Overhead 3D rendering of an A-frame cabin dining table with globe pendants, galley kitchen and white staircase, Muskoka, Canada — Kitchen along one wall, dining table in the middle and the garden beyond: the classic rear extension layout seen from above.

Layout 2: kitchen in the original house, dining and living in the extension

The kitchen stays in, or moves to, the original back room, and the new extension becomes a dining and living space with the glazing.

Works with: shallower extensions, or when you want a sofa area as well as a table
Why it works: plumbing often stays close to where it is now, and the bright new space is used for sitting rather than cooking
Watch for: the kitchen ending up in the darkest part of the room. Plan rooflights over the kitchen end

Layout 3: island facing the garden

A long island runs across the room, parallel to the glazing, with the cooking run behind it on the party wall side and the dining table between the island and the doors.

Works with: wider houses and deeper extensions, around 4 metres or more
Why it works: whoever is cooking looks straight out to the garden and talks to people at the table
Watch for: depth. Island, walkway, table and chairs all stacked front to back need more room than they appear to on a plan

Layout 4: broken-plan with a snug

Instead of one huge open room, a partial wall, a change in floor level or a slatted screen separates the kitchen-diner from a smaller snug or TV area.

Works with: deeper extensions and households where one person cooks while others want to watch television
Why it works: you keep the light and the connection without the noise
Watch for: cutting the light off from the snug. Glazed or slatted divisions help

Interior rendering of a dark slatted wood room divider and backlit walnut display shelving in front of the kitchen, Lebanon apartment renovation — A slatted timber screen separates zones without blocking the light: broken-plan living for a deeper extension.

The middle-of-the-house problem

The most common regret with rear extensions is not in the extension at all. It is the room behind it. When you build out from the back of the house, the original back room loses its windows and can become a dark, gloomy link between the front of the house and the new space.

Solutions to plan in from the start:

Rooflights or a roof lantern positioned over the join, not only at the far end
A glazed or partly glazed roof strip along the original wall line
Lighter floors and finishes running continuously through old and new
Moving the darkest functions, such as a utility or pantry, into that middle zone

A 3D render with realistic daylight shows exactly how much light reaches the middle of the house before the roof is designed.

Glazing choices

Bifold doors open the whole width but leave a stack of frames when open. Sliding doors have slimmer frames and better views when closed. A large fixed pane with one door is often the most elegant and the most thermally efficient. Look at how each looks from inside, sitting at the table, not only on the elevation drawing.

3D rendering of a round wood dining table with cream boucle chairs and a wall of mirrored panels in warm sunset light, Upstate New York home — Where the dining table sits relative to the glazing decides how the whole room feels at different times of day.

Visualise the layout before you commit

Choosing between these layouts is far easier when you can see each one in your own house. We model the existing house and the proposed extension, then render the kitchen-diner with real furniture, finishes and daylight, from where you will actually sit. If you are torn between two layouts, a second design option is an add-on.

Open-plan kitchen, dining and living spaces start at £749 in the UK. See our extension and addition rendering service and our guide to visualising your extension before planning.

Plan the services early

The layout decides where the kitchen goes, and the kitchen decides where the services go. These are the items that most often cause late changes and extra cost.

Drainage. Find out where the existing drains run. A sink or dishwasher far from the drain may need a pump or a new run under the floor. In many terraced and semi-detached houses a shared drain runs under the back of the house, and building over it can need your water company's agreement.
Steel beams. Opening the rear wall needs a steel beam, sometimes more than one. Ask whether a flush beam is possible, because a downstand beam across the middle of the ceiling visually splits the new room from the old one.
Heating. Large glazed rooms lose heat fast. Underfloor heating is common in extensions and frees the walls for kitchen units.
Extraction. An island hob needs either a ceiling extractor or a downdraft, both of which need routing.
Electrics. Decide the island position before first-fix electrics so sockets and pendant points land in the right place.

Kitchen-diner checklist

Is there at least 1000 mm, ideally 1200 mm, around the island?
Can you walk from the house to the garden without crossing the cooking area?
Does the dining table sit in good light and close enough to the kitchen to serve easily?
Where does the sofa or snug go, and what does it look at?
Where do bins, recycling and a utility area go?
How will daylight reach the middle of the house?

Frequently asked questions

How deep should a single-storey rear extension be for a kitchen-diner?

Around 3 metres of new depth, combined with an opened-up existing room, is enough for a kitchen along one wall and a dining table. Layouts with an island facing the garden usually need 4 metres or more.

How do I stop the middle of the house getting dark?

Place rooflights or a lantern over the join between old and new, carry light floor finishes through, and consider putting a utility or pantry in the darkest zone.

Bifold or sliding doors for a rear extension?

Bifolds open the full width; sliding doors have slimmer frames and better views when closed. Look at both from inside the room before deciding.

Can I see my extension layout in 3D before building?

Yes. We render your actual house with the proposed extension, furniture and daylight, so you can compare layouts before planning or building control.

Send a short brief with your plans or a sketch and we will reply within 24 hours.