Part single, part two-storey extensions in Abingdon

Quick reference for homeowners in Abingdon.

Postcode districts: OX13 and OX14
County / area: Oxfordshire, 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: Didcot (4.6 miles), Cowley (5.3 miles), Oxford (5.7 miles)
Distance to Oxford: about 5.7 miles
First visit: Free, no obligation

About a part single, part two-storey extension

A part single, part two-storey extension is an extension where the ground floor is wider or deeper than the floor above, so only part of it rises to two storeys. It usually gives a large kitchen or living area with roof lights below and one bedroom or bathroom above. It is often a good way to add space while limiting the effect on neighbours.

Abingdon sits about 5.7 miles from Oxford. Closer to home, Didcot is 4.6 miles away and Cowley 5.3 miles.

What it costs in Abingdon

Guide prices for part single, part two-storey extensions in South East England are around £2,200–£3,030 per m² of new floor space, including VAT. For a typical project with a 6 m × 4 m ground floor and a first floor over half of it (36 m² in total), that's roughly £79,000–£109,000. The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.

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 Abingdon

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 Abingdon homes

Structure at the step

The first-floor wall above often sits over the new open-plan space, so it needs a steel beam or frame to carry it. Loads come down at different points than in a full two-storey design, and the engineer sizes the foundations to suit each part.

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

Understand the brief
At your home in Abingdon we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Get it approved
Once you're happy with the design we submit it to the council for Abingdon and deal with any questions from the planning officer.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
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 Abingdon

Which postcodes do you cover around Abingdon?

We cover Abingdon (OX13 and OX14) and nearby places including Didcot, Cowley and Oxford, plus the rest of Oxfordshire. The first site visit is free.

Who handles building regulations for a project in Abingdon?

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 Abingdon?

Our guide for South East England, which covers Abingdon, 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 the single-storey part be deeper than the two-storey part?

With planning permission, yes, and that is often the point of the design: the ground floor projects further into the garden while the first floor stays back from neighbours. Under permitted development, the depth limits for extensions of more than one storey can apply to the whole extension, so we confirm which route applies before drawings are finalised.

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

Close to Abingdon? We work across the area, including:

Other extensions in Abingdon

All two-storey extension services in Abingdon · Part single, part two-storey extensions across Oxfordshire

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