Two-storey extensions for semi-detached houses in Shirley (West Midlands)

Shirley (West Midlands): the key facts for this kind of project.

Postcode districts: B14, B28 and B90
County / area: West Midlands, England
Price region: West Midlands
Guide price: £56,000–£75,500 (£2,000–£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: Solihull (1.6 miles), Acocks Green (2.7 miles), Knowle (4.1 miles)
Distance to Birmingham: about 5.9 miles
First visit: Free, no obligation

About a two-storey extension for a semi-detached house

A two-storey extension for a semi-detached house is a two-floor addition to the rear, the open side, or both, designed around the attached neighbour on one side. The rear is often the simplest option and can sometimes be permitted development, while a side extension uses the gap on the detached side. Both need care with the shared party wall and the neighbour's light.

We cover Shirley (West Midlands) (B14, B28 and B90) and the places around it, including Solihull (1.6 miles), Acocks Green (2.7 miles) and Knowle.

What it costs in Shirley (West Midlands)

A guide price for Shirley (West Midlands): around £56,000–£75,500 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). That works out at £2,000–£2,700 per m² of new floor space, including VAT at 20%. We'll give you a written design-stage price first, then a fixed build price once the drawings are agreed.

Spec	Per m²	A 4 m × 3.5 m footprint on two floors (28 m² of new floor space)
Essential	£1,840–£2,480 per m²	£51,500–£69,500
Standard	£2,000–£2,700 per m²	£56,000–£75,500
Premium	£2,400–£3,240 per m²	£67,000–£90,500

Planning and building regulations in Shirley (West Midlands)

In England, a two-storey rear extension on a semi can be permitted development if it goes no more than 3 m beyond the original rear wall and stays 7 m from the rear boundary, with matching materials and roof pitch. A two-storey side or wraparound extension always needs planning permission, costing £548 (or £575 for applications made from 8 December 2026). Protected areas such as conservation areas exclude two-storey rear permitted development.

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 Shirley (West Midlands) homes

Rear, side or both

On a semi, a rear extension sits against the attached neighbour, while a side extension faces the detached neighbour and the street. We compare the space, cost and approval route for each, and for a wraparound, before you commit to one design.

The attached neighbour's light

A two-storey rear extension next to the party wall can take light from the neighbour's rear windows. Councils often use a 45-degree test, so the first floor may need to be shorter than the ground floor or set in from the shared boundary.

How we'd run your project

Understand the brief
At your home in Shirley (West Midlands) 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 Shirley (West Midlands) 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.
Build and sign-off
Vetted teams working under S&K build the extension, and we arrange the building control completion certificate at the end.

Questions about two-storey extensions for semi-detached houses in Shirley (West Midlands)

How long does a two-storey extension for a semi-detached house 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 Shirley (West Midlands)?

We cover Shirley (West Midlands) (B14, B28 and B90) and nearby places including Solihull, Acocks Green and Knowle, plus the rest of the West Midlands. The first site visit is free.

Do I need planning permission for a two-storey extension for a semi-detached house in Shirley (West Midlands)?

Shirley (West Midlands) 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.

Does a two-storey extension add value to a semi-detached house?

It usually adds value, but the gain is never certain. Nationwide's 2025 research found that 10% more floor area was linked to about 5% higher value, and that adding a double bedroom and bathroom to a three-bed, one-bathroom house could add up to 24%. Every street has a ceiling price, so check local sales first.

Will a side extension make my semi look like a terrace?

It can if it fills the whole gap to the boundary at first floor and the neighbour does the same. Many councils ask for a first-floor gap to the side boundary or a set-back for this reason. We design the extension to keep the semi reading as one of a pair.

Nearby

We also cover places near Shirley (West Midlands), including:

Other extensions in Shirley (West Midlands)

All two-storey extension services in Shirley (West Midlands) · Two-storey extensions for semi-detached houses across the West Midlands

Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in Shirley (West Midlands).