Single-storey rear extensions in Nottingham
A single-storey rear extension adds one new ground-floor room, or enlarges an existing one, across the back of your house. This page covers the decisions that are specific to building one: the roof, how deep and how high you can go, what happens near the boundary and what goes on below ground.
We survey, design, handle the approvals and build single-storey rear extensions across Nottingham and nearby towns.
- Flat, pitched and lantern roof designs
- Permitted development and prior approval checked at survey
- A written, itemised quotation
- Prefer to talk? Call 0115 990 2782
What a single-storey rear extension involves
It’s one storey, built off new foundations against the original back wall, with a roof that either sits against the house or stands as its own gable. Once the shell is weathertight, the old rear wall is usually opened up with a steel beam so the extension joins the room behind it.
It’s the most common way to extend because nothing changes upstairs, there’s no new staircase, and it’s the type most likely to fit within permitted development. It works on Victorian and Edwardian terraces, interwar semis and newer estate houses alike, though each brings its own issues with foundations, drains and neighbours.
Most people use the space for a kitchen-diner, a family room, a utility or a ground-floor WC. If the kitchen is the main reason for extending, our kitchen extensions guide covers layout and services in more detail.
Best for
Adding ground-floor living space that opens onto the garden, without building upwards or changing the rooms above.
Typical size
Many add between 3m and 6m of depth, which usually gives around 15 to 30 square metres of new floor space depending on the width of the house.
Choosing a roof: flat, pitched or lantern
The roof affects the look, the height near your neighbour, the light inside and the cost. It’s often the first design decision we make together.
Flat roof
The most common choice for single-storey rear extensions because it keeps the height down, which matters near boundaries and below upstairs windows. Modern flat roofs use a membrane such as EPDM, GRP or single-ply, laid to a slight fall so water runs to a gutter or outlet. Rooflights are easy to add.
Pitched or lean-to roof
A sloping tiled roof that matches the main house, suited to period properties and to schemes where appearance matters. The pitch needs height, so on a deep extension the eaves and ridge can get close to the permitted development and boundary limits. It allows a vaulted ceiling inside.
Roof lantern or rooflights
A lantern is a raised glazed frame set into a flat roof, usually over a dining table or island. Flat rooflights sit lower and cost less. Both bring daylight into the middle of a deep room, but they need careful detailing to avoid leaks and condensation, and they count towards the glazing allowance in building regulations.
How deep and how high: the permitted development limits
A single-storey rear extension to a house may fall under permitted development (Class A), depending on the property and any restrictions. In outline, the national rules are:
- Depth – up to 3m beyond the original rear wall of an attached house (terraced or semi-detached), or 4m for a detached house.
- Deeper with prior approval – up to 6m (attached) or 8m (detached) through the larger home extension route. Neighbours are notified and can object. Not available in conservation areas or on other Article 2(3) land.
- Height – no more than 4m at the highest point.
- Within 2m of a boundary – eaves no higher than 3m.
- Eaves and ridge – no higher than those of the existing house.
- Garden coverage – extensions and outbuildings together can’t cover more than half the land around the original house.
- Materials – similar in appearance to the existing house.
These rights don’t apply to flats, maisonettes or listed buildings, and they can be removed by an Article 4 direction or a condition on an earlier permission. Earlier extensions count towards the limits. Your property needs to be checked before you rely on permitted development, and a Lawful Development Certificate gives formal confirmation. Building regulations approval is needed either way.
Why the 2m rule shapes the roof
On most semis and terraces the extension sits within 2m of the neighbour’s boundary, so the eaves on that side must be 3m or lower. A flat roof usually fits comfortably. A pitched roof may need a shallower pitch or a lower wall, or a planning application instead.
Building on the boundary
Building up to or on the boundary, or digging within 3m of a neighbour’s building, can bring in the Party Wall etc. Act 1996, which means serving notice on the neighbour before work starts.
Foundations and drainage
Foundations are designed for the ground, not picked off a shelf. Most single-storey extensions use strip or trench-fill foundations, but shrinkable clay near trees, made-up ground or soft spots can mean going deeper or using an engineered design such as a reinforced raft or piles. Building control inspects the trenches before any concrete goes in.
Drains are the other common unknown. There’s often a soil stack, gully or inspection chamber against the back wall, and on many terraced and semi-detached streets a shared or public sewer runs across the rear gardens. Building over or close to a public sewer needs the water company’s agreement, and existing drains may need rerouting or a new manhole.
Rainwater from the new roof has to go somewhere: into an existing surface water drain, or a soakaway if the ground drains well enough. Inside, the new floor needs to line up with the existing floor while staying above outside ground level, with the damp-proof course and membrane properly joined to the house.
What we check at survey
- Trees nearby and likely soil type
- Where the drains, manholes and soil stack run
- Any public sewer close to the back wall
- Neighbours’ walls and foundations
- Access for digging and deliveries
How we build a single-storey rear extension
Free site survey
We measure up, check the drains, ground and boundaries, and talk through what you want and your budget.
Design and roof choice
Layout, roof type, glazing and where the steel will go, drawn up for you to review.
Written quotation
An itemised price for the agreed design, so you can see what’s included.
Approvals
Permitted development check, prior approval or planning if needed, building regulations and any party wall notices.
Groundworks and shell
Foundations, drainage, floor slab, walls and roof, made weathertight while the old wall stays in place.
Knock-through and fit-out
The steel goes in, the rear wall comes out, then electrics, plastering, flooring and decoration.
Sign-off and handover
Final building control inspection, a walk-through with you and handover of the paperwork.
Single-storey rear extension costs
| Extension type | Approx size | Indicative guide range |
|---|---|---|
| Small rear extension | Up to 15 sq m | £30,000 – £42,000 |
| Standard rear extension | 15 to 25 sq m | £42,000 – £62,000 |
| Large kitchen-diner extension | 25 to 35 sq m | £62,000 – £85,000 |
| Premium finish and glazing | Roof lantern, bi-folds | Add £8,000 – £18,000 |
These are indicative guide ranges, not quotes. For a single-storey rear extension the biggest variables are the foundation design, any drains that need diverting or building over, the roof type and the size of steel needed to open up the back wall. You receive a written, itemised quotation after a free site survey.
How long it takes
Most single-storey rear extensions take around 8 to 12 weeks on site, depending on size, ground conditions and finish. That’s an indicative figure, not a guarantee.
Before work starts, allow time for design and approvals. If the scheme is permitted development within the standard limits, there’s no planning application, though you may want a Lawful Development Certificate. A prior approval application gives the council 42 days to decide. Building regulations and, where needed, party wall notices run alongside.
Living at home during the build
Most people stay put. The old back wall stays in place while the shell goes up, so the house stays closed off from the site for most of the build. The disruption peaks when the wall is opened up.
Single-storey rear extensions across the area
Not sure if we cover your street? Give us a call and we will let you know.
See the work before you decide
Photos of our extension work are in the project gallery, and customer feedback is on our reviews page, where reviews are published once they’ve been matched to a real job. At your survey, ask us for a past customer you can speak to about a similar single-storey extension.
Single-storey rear extension questions
As an indicative guide, most small to standard single-storey rear extensions fall between £30,000 and £62,000, and larger kitchen-diner extensions between about £62,000 and £85,000. A roof lantern and bi-fold doors can add £8,000 to £18,000. You receive a written, itemised quotation after a free site survey.
Under permitted development, usually up to 3m from the original rear wall of a semi-detached or terraced house and 4m for a detached house, with a maximum height of 4m. Prior approval can allow up to 6m or 8m. Your house needs to be checked first, because conservation areas, listed buildings, Article 4 directions and earlier extensions can all change the answer.
A flat roof keeps the height down, suits most boundary situations and makes rooflights and lanterns easy. A pitched roof can look more in keeping with an older house but needs more height, which can push a deep extension beyond the permitted development limits near a boundary. We show you both options at design stage where they’re feasible.
You can build up to the boundary, but under permitted development any part within 2m of it must have eaves no higher than 3m. Building on the line, or digging within 3m of a neighbour’s building, usually means serving notice under the Party Wall etc. Act 1996.
It’s common. Private drains can usually be rerouted or given a new manhole. Building over or near a public sewer needs your water company’s agreement before work starts, and the design may need to allow for it. We check drain positions at the survey.
Most single-storey rear extensions take around 8 to 12 weeks on site, depending on size, ground conditions and finish. Design and approvals come first. We talk you through the expected programme with your quotation, but it’s an estimate rather than a guarantee.
Usually, yes. The old rear wall stays in place while the new shell is built, which keeps most of the dust and noise outside. The disruption peaks when the wall is opened up and the new room is joined to the house.
Get a price for your single-storey rear extension
Book a free site survey. We’ll check the permitted development position, look at the drains and ground, and follow up with a written, itemised quotation.