Two-storey extensions for detached houses in Killamarsh

Killamarsh: the key facts for this kind of project.

Postcode districts: S21
County / area: Derbyshire, England
Price region: East Midlands
Guide price: £84,500–£113,000 (£2,010–£2,700 per m²)
Approval route: Depends on position: a two-storey rear extension may be permitted development (3 m deep, 7 m from the rear boundary); a two-storey side extension needs planning permission.
Nearest towns: Beighton (0.9 miles), Staveley (4.2 miles), Dinnington (5.7 miles)
Distance to Derby: about 28.5 miles
First visit: Free, no obligation

About a two-storey extension for a detached house

This service suits you if you own a detached house and want a substantial amount of extra space, whether a side extension over a drive, a rear extension into the garden or a wraparound. You get a survey of the whole plot, options that compare layouts and costs, the approvals your nation needs, structural design and the build, carried out by vetted teams working under S&K.

We cover postcode district S21 in and around Killamarsh, along with neighbouring Beighton, Staveley and Dinnington.

What it costs in Killamarsh

Our guide for the East Midlands is £2,010–£2,700 per m² including VAT. On a project with a 3 m × 7 m footprint on two floors (42 m² of new floor space), that puts a two-storey extension for a detached house in Killamarsh at roughly £84,500–£113,000. Professional fees for drawings and the structural engineer are listed separately on our prices page.

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 Killamarsh

In England, a two-storey rear extension on a detached house can be permitted development within 3 m of the original rear wall and at least 7 m from the rear boundary, with matching roof pitch and materials, outside protected areas. Any two-storey side or wraparound extension needs planning permission, costing £548 (or £575 for applications made from 8 December 2026), with a decision due within 8 weeks of validation.

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 Killamarsh homes

Keeping it subordinate

Large detached houses can take a large extension, but councils still expect it to look secondary to the main house. A lower ridge, a modest set-back at the front and matching materials keep the proportions right, even on a wide plot.

Larger spans and steelwork

Bigger extensions often mean wider openings and longer spans, which need more steel and sometimes a steel frame. The engineer designs these early, because the size of the steel affects ceiling heights, floor depths and the cost.

How we'd run your project

Measure and listen
A visit to Killamarsh to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Questions about two-storey extensions for detached houses in Killamarsh

Do I need planning permission for a two-storey extension for a detached house in Killamarsh?

Killamarsh is in England, so England planning rules apply. Depends on position: a two-storey rear extension may be permitted development (3 m deep, 7 m from the rear boundary); a two-storey side extension needs planning permission. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Who handles building regulations for a project in Killamarsh?

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.

How much does a two-storey extension for a detached house cost in Killamarsh?

Our guide for the East Midlands, which covers Killamarsh, 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 extend a detached house on both sides?

Sometimes. With planning permission, a council may accept extensions on both sides if the house stays well proportioned and keeps gaps to the boundaries. It is more common to extend on one side and the rear, or with a wraparound. We look at the plot as a whole before suggesting more than one extension.

Is a detached house extension a better investment than moving?

It often costs less than the gap between your house and a larger one nearby, once property tax, legal fees and removal costs are counted, but that depends on your area. Extending also has limits: every street has a ceiling price. We give you build costs so you can compare them with local asking prices.

Nearby

Nearby towns we cover for two-storey extensions for detached houses:

Other extensions in Killamarsh

All two-storey extension services in Killamarsh · Two-storey extensions for detached houses across Derbyshire

The quickest next step is a visit. We'll look at your house in Killamarsh and give you an honest view of the options.