Side extensions in York: design, approvals and build
Planning a side extension in York? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in YorkFrom £20,500 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsYO1, YO10, YO23, YO24, YO30
Will the council need to approve it?
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
When a side extension makes sense
- Homes needing a utility, study or ground-floor bedroom
- Detached and semi-detached houses with side land
- Houses where the rear garden is small
Councils often prefer side extensions to sit slightly back from the front of the house with a lower roof, so the original building still reads clearly. We design to those principles from the start to avoid redesigns.
What should I budget for a side extension in York?
For York we adjust our national guide rates by ×0.94, the factor we use for Yorkshire and the Humber. Figures include VAT; your written quote after the survey replaces them.
Typical rates in York: £1,640 to £3,200 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £20,500 – £25,000 | £23,000 – £30,000 | £29,000 – £38,500 |
| 3 m × 6 m 18 m² | £29,500 – £36,000 | £34,500 – £45,000 | £43,500 – £58,000 |
| 3 m × 8 m 24 m² | £39,000 – £47,500 | £46,000 – £60,000 | £58,500 – £77,000 |
Try the guide-price tool to see a range for your own size and finish.
Extensions in and around York
We cover York and the postcode districts YO1, YO10, YO23, YO24, YO30, YO31. Nearby, we also take on projects in Selby (12 miles), Harrogate (19 miles), Ripon (24 miles), Northallerton (31 miles).
For homes towards East Riding of Yorkshire, Goole is around 19 miles away. Yorkshire and the Humber combines stone-built terraces in the Pennine towns with brick semis and newer estates elsewhere, so materials and roof details need matching with care.
How the project works
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
We visit your York home, measure up, talk through what you want and check the planning position.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions people ask about side extensions
How long does a side extension take to build in York?
On site, typically 10 to 18 weeks once approvals are in place. Before that, allow 6–14 weeks design and approvals.
Do you cover all of York?
Yes. We cover York and the surrounding parts of North Yorkshire. Site visits are free and there is no obligation.
Will my neighbours in York 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.
Can I build a side extension without planning permission?
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a planning application.
How much does a side extension cost?
Our guide range is about £1,640 to £3,200 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £34,500 to £45,000 in York.
Book a free site visit in York
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.