Two-storey rear extensions in Old Swan

Quick reference for homeowners in Old Swan.

Postcode districts: L13
County / area: Merseyside, England
Price region: North West England
Guide price: £53,000–£72,000 (£1,900–£2,560 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: Knotty Ash (0.5 miles), Wavertree (1.1 miles), Childwall (1.3 miles)
Distance to Liverpool: about 2.9 miles
First visit: Free, no obligation

About a two-storey rear extension

A two-storey rear extension is a new two-floor addition built onto the back of your house, usually giving a larger kitchen or living space on the ground floor and one or two bedrooms or a bathroom above. Because both floors share one set of foundations and one roof, it adds a lot of floor space for the garden it uses. In some cases it can be built under permitted development, depending on where you live.

Old Swan sits about 2.9 miles from Liverpool. Closer to home, Knotty Ash is 0.5 miles away and Wavertree 1.1 miles.

What it costs in Old Swan

Most of the cost of a two-storey rear extension is set by its size and specification. For Old Swan and the rest of North West England, our guide is £1,900–£2,560 per m² including VAT, so about £53,000–£72,000 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). Keep a contingency of around 10% for things nobody can see until the ground is opened up.

Spec	Per m²	A 4 m × 3.5 m footprint on two floors (28 m² of new floor space)
Essential	£1,750–£2,360 per m²	£49,000–£66,000
Standard	£1,900–£2,560 per m²	£53,000–£72,000
Premium	£2,280–£3,080 per m²	£64,000–£86,000

Planning and building regulations in Old Swan

In England, a two-storey rear extension can be permitted development if it goes no more than 3 m beyond the rear wall of the original house, stays at least 7 m from the rear boundary and matches the house's materials and roof pitch. It is not permitted development in conservation areas, National Landscapes, National Parks, World Heritage Sites or the Broads. Otherwise a householder application costs £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 Old Swan homes

Opening up the ground floor

Knocking through the old rear wall means steel beams to carry the first floor and roof above. The structural engineer sets the beam sizes, padstones and any posts, and we plan them early so the open-plan layout you want is the one that gets built.

Roof form

A hipped or gabled roof that matches the pitch of the main house usually looks best, and matching the pitch is a permitted development condition in England. Keeping the ridge below the main ridge makes the extension read as secondary and avoids awkward junctions with existing gutters and windows.

How we'd run your project

Start at your house
We come to your home in Old Swan, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
Get it approved
Once you're happy with the design we submit it to the council for Old Swan and deal with any questions from the planning officer.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
Build and hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.

Questions about two-storey rear extensions in Old Swan

How long does a two-storey rear 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.

Which postcodes do you cover around Old Swan?

We cover Old Swan (L13) and nearby places including Knotty Ash, Wavertree and Childwall, plus the rest of Merseyside. The first site visit is free.

Who handles building regulations for a project in Old Swan?

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.

Can I have a balcony on a two-storey rear extension?

In England, balconies, verandas and raised platforms are not permitted development, so a balcony on a two-storey rear extension needs planning permission. A Juliet balcony, a guard rail across full-height doors with no platform to stand on, is often a practical alternative, but it still needs checking against the rules and the council's approach to overlooking.

Will a two-storey rear extension block my neighbour's light?

It can if it is too deep or too close to the boundary, which is why councils look closely at its effect on neighbouring windows and gardens. We test the design against light and outlook early, keep the first floor shorter or set in where needed, and use a hipped roof to reduce bulk on the boundary side.

Nearby

Nearby towns we cover for two-storey rear extensions:

Other extensions in Old Swan

All two-storey extension services in Old Swan · Two-storey rear extensions across Merseyside

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