If you’re running out of space at home, a single-storey extension is one of the most practical ways to add the room you need — without the upheaval of moving. Whether you’re after a bigger kitchen, an open-plan living area, a home office or a utility room, DJF Building helps homeowners across Staffordshire and the West Midlands make it happen.

But one of the first questions everyone asks is: how much is it actually going to cost?

This guide gives you straight, honest figures for 2026 — no vague ranges, no hidden extras glossed over.

What Does a Single-Storey Extension Cost in Staffordshire?

Cost per square metre

In the Midlands, single-storey extensions typically cost between £2,000 and £3,000 per square metre for a mid-range finish. That includes everything from groundworks and foundations through to plastering, windows, doors and decoration — in other words, a finished, usable room.

Here’s how that breaks down by build quality:

  • Budget/basic finish: around £1,500–£1,800/m²
  • Standard/mid-range finish: £2,000–£2,600/m²
  • High-spec finish (bi-fold doors, underfloor heating, premium materials): £2,700–£3,500/m²

Most builder quotes are VAT-exclusive. If your builder is VAT-registered, remember to add 20% to the headline figure.

Example project costs

To give you a clearer picture:

  • 3m × 4m (12m²) — small rear extension: £24,000–£36,000
  • 4m × 5m (20m²) — typical kitchen-diner extension: £40,000–£60,000
  • 5m × 6m (30m²) — larger open-plan addition: £60,000–£90,000

These are realistic mid-range figures for Burntwood, Cannock, Lichfield, Walsall and surrounding areas. You won’t find the London premium here — but equally, we’re not cutting corners to hit an artificially low price.

What Affects the Cost?

Several things push the price up or down, and it’s worth understanding them before you get quotes.

Size and shape — the biggest factor by far. More square metres means more cost. Irregular shapes, deep returns or wrap-around designs add complexity.

Groundworks and foundations — this is where surprises happen. Parts of Staffordshire sit on former coal mining land, and if your property is in an at-risk area, you may need deeper or piled foundations. That can add £3,000–£8,000 to the groundworks bill. A thorough builder will investigate this before quoting.

Roof type — a flat roof with a modern EPDM membrane is the most common and affordable choice. A pitched roof costs more but blends better with some properties. Roof lanterns or skylights cost extra but can transform how a room feels.

Glazing — bi-fold or sliding doors and large windows significantly increase costs but are very popular for rear extensions opening onto a garden.

Internal fit-out — if your extension includes a new kitchen, bathroom or utility room, plumbing and electrics are additional to the build cost and should be quoted clearly and separately.

Your existing property — older homes sometimes throw up surprises: drains that need rerouting, walls that need underpinning, or structural work to the opening between old and new. A good builder flags these before work starts — not after.

Do You Need Planning Permission?

Most single-storey rear extensions in Staffordshire fall under Permitted Development rights, which means you don’t need full planning permission as long as you stay within certain limits:

  • Detached houses: extend up to 4 metres to the rear without planning permission
  • Semi-detached and terraced houses: up to 3 metres

Under the Larger Home Extension Scheme, those limits increase to 8m for detached properties and 6m for semis and terraces — but this route requires a Prior Approval application and a 21-day neighbour consultation with your local council.

Other rules to be aware of: maximum height is 4m (3m if within 2m of a boundary), and extensions can’t cover more than 50% of your original garden space.

If your home is in a conservation area, an Article 4 Direction zone, or is listed, Permitted Development rights are likely restricted or removed entirely. In those cases, a full planning application is required, which currently costs £206 to submit.

Not sure where you stand? We’re happy to talk it through before you commit to anything. Get in touch with DJF Building here.

How Long Does a Single-Storey Extension Take?

On-site, a typical single-storey extension takes 10 to 16 weeks from groundworks starting to practical completion. More complex builds — anything with structural steelwork, unusual glazing, or involved drainage diversions — can stretch to 20 weeks.

But on-site time is only part of the picture. Before work starts, you’ll typically need:

  • Design drawings: 2–4 weeks
  • Building Regulations submission and approval: 4–6 weeks
  • Party wall agreements, if applicable: allow at least 2 months if neighbours don’t respond promptly

From initial decision to moving into your new room, budget 4–6 months realistically — sometimes less for straightforward projects.

Costs People Often Forget to Budget For

A few things regularly catch homeowners off guard:

Architect or designer fees — typically 7–15% of the build cost, or sometimes a fixed fee. For a £50,000 extension, that’s £3,500–£7,500 on top.

Building Regulations fees — you’ll need a Building Regulations application, whether through your local council or an Approved Inspector. Typically £600–£1,200 for a residential extension.

Party wall agreement — if your extension sits near a shared boundary, you’re likely to need a Party Wall Surveyor. Costs range from £1,000–£2,500 depending on whether your neighbour appoints their own surveyor or agrees to share one.

Temporary disruption — depending on the extent of the work, you might need to budget for eating out more, temporary storage, or even short-term accommodation for a phase of the build.

Frequently Asked Questions

Does a single-storey extension add value to my home?

Generally yes. A well-built extension that adds usable living space typically returns more than its cost at resale. Open-plan kitchen-diners and additional reception rooms are particularly popular with buyers across the Staffordshire area.

Can I live in my house while the extension is being built?

In most cases, yes. The majority of the work is external until the new space is connected to the existing house. At DJF Building we take care to protect the rest of your home during work and keep disruption to a minimum.

Do I need an architect?

Not always. For simpler builds, an architectural technician can produce the drawings you need for Building Regulations. For more complex designs or full planning applications, a qualified architect adds real value.

Will my extension need Building Regulations approval?

Yes — all extensions require Building Regulations approval regardless of whether they need planning permission. This covers structural integrity, insulation, ventilation, drainage and fire safety. Your builder should handle this process or guide you through it clearly.

Get a Free Quote for Your Extension

If you’re thinking about extending your home in Staffordshire, we’d love to help. At DJF Building, we give honest quotes, explain everything clearly, and only take on work we can do properly. No hidden costs, no pressure.

We serve homeowners across Burntwood, Cannock, Lichfield, Walsall, Stafford and the wider West Midlands. Take a look at our full range of building services, or get in touch today for a free, no-obligation quote.