What is a side extension?

A side extension builds into the space beside a semi-detached or detached house, often over a driveway or side passage. It can be single-storey, for a utility room, downstairs toilet or study, or two-storey to add a bedroom above.
How much does a side extension cost in Kirkby in Ashfield?
In Kirkby in Ashfield, a side extension typically costs £1,600–£2,500 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £45,000–£70,000. The guide for Kirkby in Ashfield reflects typical costs in the East Midlands, roughly 5% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (20 m²) | £32,000–£50,000 |
| Typical project (28 m²) | £45,000–£70,000 |
| Larger project (39 m²) | £62,500–£97,500 |
| Rate per m² | £1,600–£2,500 |
The main things that change the cost:
- Boundary walls and access for materials
- Roof design and tile matching
- Internal fit-out of the new rooms
- Steel work where the side wall is opened
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a side extension in Kirkby in Ashfield?
Here is how the rules work for a side extension in England. In England a single-storey side extension can be permitted development if it is no more than 4 metres high and no wider than half the width of the original house. Side extensions of more than one storey always need planning permission, as do side extensions in conservation areas, National Parks and National Landscapes.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
Handled as part of most side extensions:
- Opening into the existing house
- Electrics, heating and plastering
- Structural calculations
- Building control completion
- Planning drawings and application
- Walls, roof and windows to match the house
How long does it take?
Build time is typically 10 to 16 weeks on site depending on size and storeys. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Kirkby in Ashfield
The East Midlands has a mix of red-brick terraces, inter-war semis and newer estates, so rear extensions and garage conversions are common projects.
Kirkby in Ashfield sits in Nottinghamshire, about 11 miles north of Nottingham. We cover the whole of Kirkby in Ashfield, including postcodes NG17.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about side extensions in Kirkby in Ashfield
Will a two-storey side extension look odd?
Not if it is designed well. Setting it back from the front and keeping the roof lower than the main ridge usually gives a natural look and is what most councils ask for.
How much does a side extension cost in Kirkby in Ashfield?
In Kirkby in Ashfield, a side extension typically costs £1,600–£2,500 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £45,000–£70,000. Your fixed price depends on the survey and drawings.
How long does a side extension take in Kirkby in Ashfield?
Typically 10 to 16 weeks on site depending on size and storeys. Design and approvals beforehand usually take 3 to 4 months.
Will I lose my driveway?
A side extension often takes the side drive. We look at whether parking can be kept at the front and whether a dropped kerb is needed.
How close to the boundary can I build?
You can build up to the boundary, but the eaves height near it is limited under permitted development, and planning officers often want a gap at first floor. If you build on or near a shared boundary, party wall rules may apply.
