Chesterfield over-garage extensions, designed and built
A over-garage extension in Chesterfield starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in ChesterfieldFrom £22,500 inc VAT
- PlanningHouseholder application needed
- Build time12–18 weeks on site
- Postcode districtsS18, S40, S41, S42, S43
Included in a typical project
- Structural survey of garage walls and foundations
- Insulation, electrics, heating and finish
- Design and householder planning application
- Opening into the existing first floor
- Strengthening or rebuilding the garage walls if needed
- New floor structure, walls and roof
Covering Chesterfield
Postcode districts we cover around Chesterfield include S18, S40, S41, S42, S43, S44. Nearby, we also take on projects in Staveley (3 miles), Dronfield (4 miles), Alfreton (11 miles), Ripley (15 miles).
For homes towards South Yorkshire, Sheffield is around 9 miles away. Homes across the East Midlands often have usable side land or a driveway beside the house, which opens up side and wraparound options.
How much does an over-garage extension cost in Chesterfield?
For Chesterfield we adjust our national guide rates by ×0.95, the factor we use for East Midlands. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Chesterfield: £1,710 to £3,230 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Over a single garage 12 m² | £22,500 – £28,000 | £23,500 – £31,000 | £30,500 – £39,000 |
| Over a large single garage 16 m² | £27,000 – £33,500 | £31,500 – £41,500 | £41,000 – £52,000 |
| Over a double garage 24 m² | £41,000 – £50,500 | £47,500 – £62,000 | £61,500 – £78,000 |
Try the guide-price tool to see a range for your own size and finish.
Do I need planning permission in Chesterfield?
In England any side extension over one storey, including a room built over a side garage, needs a householder planning application. The fee is £548 from 1 April 2026 and councils aim to decide within 8 weeks.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
Our process, step by step
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Over-garage extension questions answered
Do you cover all of Chesterfield?
Yes. We cover Chesterfield and the surrounding parts of Derbyshire. Site visits are free and there is no obligation.
Will my neighbours in Chesterfield be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Do I need building regulations approval in Chesterfield?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can my garage take the weight of a room on top?
Some can and some cannot. Many garages have a single-skin wall or shallow foundations. Our structural engineer checks this before we give a fixed price.
How much does a room over a garage cost?
Our guide range is about £1,710 to £3,230 per m² including VAT. A single-garage room of about 12 m² usually costs £23,500 to £31,000 at standard spec, more if the garage needs rebuilding.
Book a free site visit in Chesterfield
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.