Two-storey side extensions in Chesterfield

The basics for Chesterfield at a glance.

Postcode districts: S40, S41 and S42
County / area: Derbyshire, England
Price region: East Midlands
Guide price: £84,500–£113,000 (£2,010–£2,700 per m²)
Approval route: Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
Nearest towns: Staveley (3 miles), Dronfield (4.3 miles), Bolsover (5.4 miles)
Distance to Derby: about 22.7 miles
First visit: Free, no obligation

About a two-storey side extension

A two-storey side extension suits a detached or semi-detached house with a side garden, driveway or garage wide enough to build on. You get a design that sits comfortably on the street, a planning application or permitted development check depending on your nation, structural design, building regulations approval and the build itself. We manage the whole process, and the work is carried out by vetted teams working under S&K.

We cover Chesterfield (S40, S41 and S42) and the places around it, including Staveley (3.0 miles), Dronfield (4.3 miles) and Bolsover.

What it costs in Chesterfield

Expect a two-storey side extension in Chesterfield to land somewhere around £84,500–£113,000 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). Our East Midlands guide rate is £2,010–£2,700 per m², including VAT. Keep a contingency of around 10% for things nobody can see until the ground is opened up.

Spec	Per m²	A 3 m × 7 m footprint on two floors (42 m² of new floor space)
Essential	£1,850–£2,480 per m²	£77,500–£104,000
Standard	£2,010–£2,700 per m²	£84,500–£113,000
Premium	£2,410–£3,230 per m²	£101,500–£136,000

Planning and building regulations in Chesterfield

In England, a two-storey side extension always needs householder planning permission, because permitted development only allows single-storey extensions beyond a side wall. The fee is £548 (or £575 for applications made from 8 December 2026), and councils should decide within 8 weeks of validation. Expect them to look at set-back, roof height, gaps to the boundary and the effect on neighbours.

Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.

Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.

Design points for Chesterfield homes

Side windows, boundaries and gutters

Upstairs windows in the side wall face the neighbour, so they are usually obscure-glazed and fixed, or left out. Building close to the boundary also raises questions about foundations, overhanging gutters and access for maintenance, so we design the eaves and gutter to stay within your land.

Set-down and set-back

Councils usually want a two-storey side extension to look subordinate to the house. Setting the front wall back from the main front and dropping the ridge slightly below the main roof helps it read as an addition, and is often expected in local design guidance.

How we'd run your project

Look at the house
We start in Chesterfield with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Design and approvals
We draw the extension and check it against the rules for England, then apply for planning permission or a certificate of lawfulness, whichever fits.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.

Questions about two-storey side extensions in Chesterfield

Who handles building regulations for a project in Chesterfield?

We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.

Do I need planning permission for a two-storey side extension in Chesterfield?

Chesterfield is in England, so England planning rules apply. Planning permission is needed: in England, permitted development only allows single-storey extensions to the side. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Which postcodes do you cover around Chesterfield?

We cover Chesterfield (S40, S41 and S42) and nearby places including Staveley, Dronfield and Bolsover, plus the rest of Derbyshire. The first site visit is free.

How much does a two-storey side extension cost in Chesterfield?

Our guide for the East Midlands, which covers Chesterfield, is £2,010–£2,700 per m² including VAT. A typical project with a 3 m × 7 m footprint on two floors (42 m² of new floor space) comes to about £84,500–£113,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Can I build a two-storey side extension over my driveway?

Yes, if the drive is wide enough for a useful room and the council accepts the design. You may lose off-road parking, which some councils weigh up, and the foundations need to suit the ground below. We check parking, drains and meter positions at the free site visit before any drawings are prepared.

Nearby

Other towns near Chesterfield:

Other extensions in Chesterfield

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Book a free site visit in Chesterfield and we'll tell you what's possible, what approvals you need and what the design stage would cost.