If your home is starting to feel a little cramped, or you’ve simply outgrown your space but love your location, a house extension could be the perfect solution. Whether you’re dreaming of a spacious open-plan kitchen, an extra bedroom, or a relaxing garden room, extending your home is a fantastic way to add both space and value.
But one of the first questions we’re often asked at J&K Developments is:
“How much does it cost to build an extension?”
While the honest answer is “it depends”, we’ve pulled together some realistic figures and guidance to help you get a clear idea of what to expect – and how we can support you from start to finish.
Typical Extension Costs in Derby, Derbyshire & Staffordshire
As a general guide, you can expect to pay between £1,800 – £2,800 per square metre for a single-storey extension, and £2,200 – £3,500 per square metre for a two-storey extension.
This range can vary depending on the following:
The size of your extension
The complexity of the build
Your choice of materials and finishes
Access to the property
Any structural or groundworks required
Planning permission and building regulations
What Type of Extension Are You Planning?
Here’s a quick look at some typical extension types and estimated starting costs:
| Type of Extension | Typical Cost Range |
|---|---|
| Single-storey rear extension (20m²) | £36,000 – £56,000+ |
| Two-storey side or rear extension (40m²) | £88,000 – £140,000+ |
| Wraparound extension | £90,000 – £160,000+ |
| Garage conversion | £15,000 – £30,000+ |
| Loft conversion | £40,000 – £70,000+ |
| Kitchen extension with fittings | £50,000 – £100,000+ |
These are ballpark figures – we always provide a fully itemised quote once we understand your project.
Why Work with J&K Developments?
We’re a family-run building company based in Derby, trusted across Derbyshire and Staffordshire for delivering high-quality extensions with professionalism and care.
Here’s how we make the process simple and stress-free:
Free consultation with our Director to understand your goals and budget Collaborative design process with our trusted architects Planning support – we deal with the local authorities so you don’t have to Transparent, itemised quotes – no surprises, just clear pricing Seamless build process – our experienced team handles every detail Aftercare and support – we’re here long after the work is done
Other Costs to Consider
Don’t forget to factor in:
Architectural drawings and planning application fees
Structural engineer costs (if required)
VAT – most residential extensions are subject to 20% VAT
Finishing touches – kitchens, flooring, bathrooms, lighting, etc.
Thinking About an Extension? Let’s Talk!
An extension is a big investment, but when it’s done right, it can completely transform the way you live in your home. At J&K Developments, we’re here to guide you every step of the way — from concept to completion.
Contact us today to book your free consultation and get a detailed, personalised quote for your extension. Let’s turn your ideas into a space you’ll love for years to come.
