Gainsborough, Lincolnshire
Single-storey rear extension in Gainsborough
Ground-floor space across the back of the house, usually for a kitchen, dining or family room. We design, get the approvals for and build single-storey rear extensions in Gainsborough and the surrounding area, with one contract from the first survey to building control sign-off.
Gainsborough is covered from our Lincolnshire round, including DN21. A single-storey rear extension in Gainsborough is mostly built from the garden side, so the house stays usable for most of the job.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a single-storey rear extension cost in Gainsborough?
A single-storey rear extension in Gainsborough is priced at £1,840–£3,010 per square metre including VAT as a guide, before kitchen fit-out and fees. East Midlands prices sit a little below our West Midlands baseline.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £22,000–£36,000 |
| 4 m wide × 5 m deep (20 m²) | £37,000–£60,000 |
| 4 m wide × 6 m deep (24 m²) | £44,000–£72,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a single-storey rear extension in Gainsborough?
Whether your single-storey rear extension in Gainsborough needs a planning application depends on its size, your house and any local restrictions.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.
What are homes in Gainsborough like to extend?
Red-brick terraces and semis are typical of Gainsborough. Coal-mining legacy areas in parts of the East Midlands can need a Coal Authority check before foundations are designed.
How a single-storey rear extension in Gainsborough comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Single-storey rear extensions near Gainsborough
Neighbouring places we cover include Retford (8.4 miles) and Scunthorpe (14.3 miles).
- Single-storey rear extension in Retford
- Single-storey rear extension in Scunthorpe
- Single-storey rear extension in Lincoln
- Single-storey rear extension in Boughton
- Single-storey rear extension in Worksop
Other work in Gainsborough:
FAQ
Single-storey rear extension questions in Gainsborough
How long does a rear extension take to build in Gainsborough?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Can you match the brick or stone on my Gainsborough house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
How deep can a single-storey rear extension be without planning?
In England, 3 metres on an attached house and 4 metres on a detached house under permitted development, or up to 6 and 8 metres with prior approval. Wales allows 4 metres; Scotland and Northern Ireland have their own limits.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Do I need planning permission for a rear extension in Gainsborough?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.