A single-storey extension is a new ground-floor room built onto your house, usually at the rear or side, with its own foundations, walls and roof, creating a bigger kitchen, living space or bedroom without moving home.
If you are planning a single-storey extension anywhere in Derbyshire, including Derby, Chesterfield, Long Eaton and Ilkeston, we can visit, measure up and talk through the options. The planning and building regulations we work to are those for England, and we check them for your address before quoting. Prices remain guide figures for the East Midlands, at £33,500–£72,000 including VAT, until the survey is done.
- Guide price
- £33,500–£72,000 inc VAT
- Time on site
- 10–16 weeks on site
- Planning rules
- England
- Price level
- About 4% below the national guide
- Towns listed
- 12
- Survey
- Free, with a written quote
How much does a single-storey extension cost in Derbyshire?
Prices for a single-storey extension vary from house to house, but in Derbyshire most projects fall within £33,500–£72,000 including VAT. That reflects costs in the East Midlands, about 4% below the national guide. Treat the table as a budgeting aid; the written figure follows a survey we carry out for free.
| Type of job | What it usually involves | Guide in Derbyshire |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £21,000–£38,500 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £33,500–£72,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £67,000–£125,000 |
What moves the price up or down:
- Roof type, rooflights, lanterns and the amount of glazing
- Ground conditions, foundation depth and drains to divert
- Steelwork needed to open into the existing house
- Finishes, kitchen, flooring and heating specification
What’s included?
- Cavity walls built and insulated to building regulations
- Flat or pitched roof, with rooflights or a lantern if specified
- Steel beams to open into the existing house
- Electrics and plumbing by qualified trades, with certificates
- Windows and external doors, including bifolds if chosen
- Building control inspections and completion certificate
Housing across Derbyshire
Derby has wide areas of Victorian red-brick terraces and interwar semis, while Peak District villages use gritstone and limestone under stone-slate or Welsh slate roofs. Former mining towns in the north-east of the county have brick terraces and post-war housing built for mining communities, and modern estates have grown around Derby, Chesterfield and the M1 corridor.
Brick terraces frequently suit loft conversions and rear extensions, and many need repointing. Stone properties in the Peak may call for lime work and planning-sensitive windows, while interwar and estate homes commonly take side extensions and garage conversions.
The High Peak gets heavy rain, snow and frequent frost, while the lower Trent valley is milder; old mine workings can also affect ground conditions in places.
Do you need permission in Derbyshire?
For anyone in Derbyshire, the relevant framework is England's. The summary below is general, so we always contact the council about your address before putting a price in writing.
In England, many single-storey rear extensions are permitted development: typically up to 3 m deep on a semi-detached or terraced house and 4 m on a detached house, no more than 4 m high, and covering no more than half the land around the original house. Larger rear extensions can go through the prior approval process. Side extensions, flats, listed buildings, conservation areas and homes where permitted development rights have been removed need planning permission.
Building Regulations approval is needed for almost every extension, covering foundations, structure, insulation, drainage, ventilation and fire safety. If the work is on or near a shared wall or boundary, the Party Wall etc. Act 1996 may apply.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
From survey to handover
A visit to your home
A free survey comes first. It gives us what we need to price a single-storey extension properly, including dimensions, existing materials and access for deliveries, and gives you the chance to ask anything you like.
Quote in writing
The quote arrives in writing, not over the phone. It covers the full scope, the finishes you've chosen, any exclusions and the payment schedule, with a fixed price tied to that specification.
Getting ready
Before anyone starts, we confirm the programme in writing, check whether consents are required and arrange deliveries. If a skip or scaffolding on the road needs a permit, we apply for it.
Build and hand over
Our trades complete a single-storey extension while your point of contact keeps you updated. When everything is finished, we clear the site, take away waste and go through the result with you before handover.
What you can expect from us
Frequently asked questions
What is the Party Wall Act and does it apply to me?
The Party Wall etc. Act 1996 applies in England and Wales only. In England and Wales, it requires you to give notice to neighbours before certain work on or near a shared wall, such as digging foundations within 3m of their building and deeper than its footings. Neighbours can agree or appoint a surveyor. Scotland and Northern Ireland have no equivalent Act, though general rights still apply. We identify whether notices are needed during the survey.
Do you cover Derby, Chesterfield and Long Eaton?
Yes. As well as Derbyshire, we cover Derby, Chesterfield and Long Eaton and the rest of Derbyshire. Our coverage is UK-wide, so the process is the same wherever you are: a free site survey, a quote in writing that fixes the price for the agreed scope, and one point of contact while the work is planned and carried out.
Do I need planning permission for a single-storey extension?
Whether you need planning permission depends on the extension's size and height, how close it is to boundaries, your home's location, whether it is listed or in a conservation area, and which UK nation you live in. In England, many rear extensions up to 3m deep on a semi or terrace, or 4m on a detached house, can be built under permitted development. We check the rules that apply to your home before quoting.
What does a typical extension build look like week by week?
A typical single-storey extension follows the same order: clearing the site and digging foundations, building walls up to roof level, then fitting the roof and windows to make it weathertight. Electrics, plumbing, insulation and plastering follow. The last stage is opening into the house, laying the screed and fitting doors and finishes. Building control inspects at key stages, and we book those visits for you.
How much will a single-storey extension cost in Derbyshire?
As a guide, expect to pay £33,500–£72,000 including VAT for a single-storey extension in Derbyshire. That range is adjusted for the East Midlands, which runs about 4% below the national guide. Where your project lands depends on size, materials, access and the condition of what is already there. We confirm a fixed price in writing after a free survey of your home.
Towns in Derbyshire
Homes in all of the following Derbyshire towns can get a written quote for a single-storey extension. Open a town page to see prices and the postcodes we cover.