Part single, part two-storey extensions in Ewell

The basics for Ewell at a glance.

Postcode districts: KT17 and KT19
County / area: Surrey, England
Price region: South East England
Guide price: £79,000–£109,000 (£2,200–£3,030 per m²)
Approval route: It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission.
Nearest towns: Cheam (1.5 miles), Epsom (1.6 miles), Worcester Park (2.1 miles)
Distance to Woking: about 13.5 miles
First visit: Free, no obligation

About a part single, part two-storey extension

A part single, part two-storey extension suits you if you want a generous ground floor but only need one extra room upstairs, or if a full two-storey design would affect a neighbour too much. You get design options that test where the two-storey part works best, the approvals your nation needs, structural design, building regulations approval and the build, carried out by vetted teams working under S&K.

Around Ewell we also work in Cheam, Epsom and Worcester Park, and across the rest of Surrey. Postcode districts in and near Ewell: KT17 and KT19.

What it costs in Ewell

Using our South East England rates, a part single, part two-storey extension with a 6 m × 4 m ground floor and a first floor over half of it (36 m² in total) comes to about £79,000–£109,000, including VAT. Bigger or more glazed designs cost more per m². Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.

Spec	Per m²	A 6 m × 4 m ground floor and a first floor over half of it (36 m² in total)
Essential	£2,020–£2,780 per m²	£73,000–£100,000
Standard	£2,200–£3,030 per m²	£79,000–£109,000
Premium	£2,640–£3,630 per m²	£95,000–£130,500

Planning and building regulations in Ewell

In England, the extension can only be permitted development if it goes no more than 3 m beyond the original rear wall and stays at least 7 m from the rear boundary, with matching materials and roof pitch. We check the whole design against the rules, including the 50% garden coverage limit. If any part fails, or extends beyond a side wall on two floors, you need planning permission, costing £548 (or £575 for applications made from 8 December 2026).

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 Ewell homes

The roof junction

Where the single-storey roof meets the two-storey wall you need a sound weathering detail, usually a lead or similar flashing, and enough height for roof lights or a lantern. We set the roof falls and the upstairs window sill heights together so they do not clash.

Where to put the two-storey part

The two-storey section usually works best away from the closest neighbour, with the single-storey part on that boundary side. We test a few positions against neighbours' windows, the upstairs layout and the roof shape before choosing the one to take forward.

How we'd run your project

Measure and listen
A visit to Ewell to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
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.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Questions about part single, part two-storey extensions in Ewell

How long does a part single, part two-storey extension take?

Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.

Who handles building regulations for a project in Ewell?

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 part single, part two-storey extension cost in Ewell?

Our guide for South East England, which covers Ewell, is £2,200–£3,030 per m² including VAT. A typical project with a 6 m × 4 m ground floor and a first floor over half of it (36 m² in total) comes to about £79,000–£109,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Can I add roof lights to the single-storey part?

Yes. Roof lights or a lantern over the single-storey part are one of the main reasons to choose this design, as they light the middle of a deep kitchen. In England they count towards the Part L glazing allowance, normally 25% of the new floor area plus windows removed, so we balance them with the rear doors.

Which side should the two-storey part go on?

Usually the side furthest from the nearest neighbour's windows, so the single-storey part sits nearest them and keeps their light. Other factors are where the stairs land upstairs, which room needs the extra space and where drains run. We sketch options at the design stage and explain which is most likely to be approved.

Nearby

Other towns near Ewell:

Other extensions in Ewell

All two-storey extension services in Ewell · Part single, part two-storey extensions across Surrey

Tell us about your house in Ewell and we'll call you back to arrange a free, no-obligation visit.