Single-Storey Extensions
The most common route to extra kitchen, dining or living space
A single-storey extension is the most common way UK households add real space without moving house — usually to the rear or side, most often extending the kitchen and dining area, and frequently the project that falls most comfortably within permitted development rights.
Single-storey extensions typically start at foundation level with a concrete strip or trench-fill foundation sized to the ground conditions and the loads the new structure will carry, then build up through blockwork or timber frame walls, a new roof — flat, pitched or a mix combining both — and connect structurally and visually into the existing house. Because there's no upper floor to support, single-storey extensions generally involve less structural complexity than a two-storey build, which is part of why they're a popular first step for households wanting more space without a larger-scale project. Many single-storey rear extensions fall under permitted development rights, subject to size limits and the specific property's planning history, though this needs checking individually rather than assumed, since previous extensions or specific local restrictions can affect what's available. The connection to the existing house is where a lot of the design decisions happen — how the new space opens onto the old, whether a supporting wall is being removed to create open-plan living, and how services (electrics, plumbing, heating) extend from the existing system into the new space. A well-built single-storey extension should feel like it was always part of the house, not an obviously bolted-on addition, which comes down to matching brick, roofline and internal finish to the existing property with real care.
When Single-Storey Extensions Is the Right Choice
- Rear or side extensions to enlarge a kitchen, dining or living space
- Projects likely to fall within permitted development, subject to individual checks
- Households wanting extra space without the complexity of a second storey
- Creating open-plan living by combining a new extension with internal wall removal
- A first-stage extension project with potential to extend upward later
What's Involved
Design & Planning
We design the extension and confirm whether permitted development applies or planning permission is needed.
Foundations & Structure
Foundations, walls and roof structure are built and tied into the existing house.
Weatherproofing
The extension is made fully weathertight, with windows and doors fitted.
Fit-Out
Plastering, electrics, plumbing, flooring and finishing complete the connected new space.
Local to South Mimms, North London & Hertfordshire
Oakwood, in the London Borough of Enfield between Cockfosters and Southgate, and Edgware, the northern terminus of the Northern line in the London Borough of Barnet, both have plenty of 1930s semis and similar houses with rear gardens well suited to a single-storey rear extension, extending the kitchen and dining space in exactly the way this extension type is most commonly used.
Single-Storey Extensions — FAQ
Q.Do single-storey extensions always fall under permitted development?
Not automatically — it depends on the extension's size, the property's planning history and any local restrictions, so we check this individually for each property rather than assuming it applies.
Q.Can a single-storey extension be built with a second storey added later?
In some cases yes, with the foundations and structure designed to allow for future extension, though this needs planning for from the outset rather than retrofitted as an afterthought.
Q.How do you make a new extension look like it belongs to the house?
By matching brickwork, roofline and internal finishes to the existing property as closely as possible, and designing the connection between old and new so it reads as one continuous building rather than an obvious addition.
Common on These Property Types
Free Single-Storey Extensions Quote
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