First-floor extensions in Oswestry

Oswestry: the key facts for this kind of project.

Postcode districts: SY10, SY11 and SY12
County / area: Shropshire, England
Price region: West Midlands
Guide price: £25,000–£36,500 (£1,800–£2,600 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: Shrewsbury (16.4 miles), Whitchurch (Shropshire) (17.1 miles), Chester (23.7 miles)
Distance to Telford: about 28.4 miles
First visit: Free, no obligation

About a first-floor extension

A first-floor extension is a new upstairs room built on top of an existing single-storey part of your house, such as a rear kitchen extension, a utility or a side annexe. It adds a bedroom, bathroom or study without enlarging the footprint. Whether it works depends mainly on whether the walls and foundations below can carry the extra load.

We cover Oswestry (SY10, SY11 and SY12) and the places around it, including Shrewsbury (16.4 miles), Whitchurch (Shropshire) (17.1 miles) and Chester.

What it costs in Oswestry

Using our West Midlands rates, a first-floor extension with 4 m × 3.5 m of new first-floor space (14 m²) comes to about £25,000–£36,500, including VAT. Bigger or more glazed designs cost more per m². The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.

Spec	Per m²	4 m × 3.5 m of new first-floor space (14 m²)
Essential	£1,660–£2,390 per m²	£23,000–£33,500
Standard	£1,800–£2,600 per m²	£25,000–£36,500
Premium	£2,160–£3,120 per m²	£30,000–£43,500

Planning and building regulations in Oswestry

In England, adding a first floor turns a single-storey extension into one of more than one storey. To be permitted development, the extension as a whole must go no more than 3 m beyond the rear wall of the original house and stay at least 7 m from the rear boundary, with matching materials and roof pitch. Over a side extension it always needs 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 Oswestry homes

Matching the roofline

A first-floor extension often changes how the back or side of the house looks more than the original single storey did. Matching the main roof pitch and materials, and keeping the ridge below the main ridge, usually gives the best result and is expected for permitted development in England.

Can the existing structure take it?

Many single-storey extensions were built with foundations, walls and lintels sized for one storey. We find out what is there with trial holes and, where available, the original building control drawings. The engineer then decides whether to reuse, strengthen or rebuild parts of the structure.

How we'd run your project

Start at your house
We come to your home in Oswestry, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
Drawings, then consent
We draw the scheme, check it against the rules in England, and take it through the right consent with the council.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Questions about first-floor extensions in Oswestry

Who handles building regulations for a project in Oswestry?

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.

Which postcodes do you cover around Oswestry?

We cover Oswestry (SY10, SY11 and SY12) and nearby places including Shrewsbury, Whitchurch (Shropshire) and Chester, plus the rest of Shropshire. The first site visit is free.

How long does a first-floor 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.

Can I build on top of my existing single-storey extension?

Often yes, but only after the structure has been checked. Foundations, walls and lintels built for one storey may not carry two. We dig trial holes, look for the original building control approval and ask the structural engineer to confirm what can stay, what needs strengthening and what must be rebuilt.

What happens to the room below while the first floor is built?

The old roof is removed, so the room below is exposed for a short period. We fit temporary weather protection, plan the work so the roof comes off only when the new structure is ready, and agree with you which rooms will be out of use and for roughly how long.

Nearby

Other towns near Oswestry:

Other extensions in Oswestry

All two-storey extension services in Oswestry · First-floor extensions across Shropshire

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