Birmingham double-storey extensions, designed and built
If you live in Birmingham and want more space without moving, a double-storey extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide price in BirminghamFrom £36,500 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsB1, B2, B3, B4, B5
Double-storey extension prices in Birmingham
These guide figures apply our West Midlands adjustment (×0.97) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Birmingham: £1,500 to £2,910 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m, two floors 24 m² | £36,500 – £44,000 | £41,500 – £55,000 | £53,500 – £70,000 |
| 4 m × 4 m, two floors 32 m² | £48,000 – £57,500 | £55,500 – £73,000 | £71,000 – £93,500 |
| 4 m × 6 m, two floors 48 m² | £72,000 – £86,500 | £83,500 – £109,500 | £107,000 – £140,000 |
Want a range for your exact size? The guide-price tool takes about a minute.
Local to Birmingham
We cover Birmingham and the postcode districts B1, B2, B3, B4, B5, B19. The same team covers Smethwick (3 miles), West Bromwich (5 miles), Shirley (6 miles), Halesowen (7 miles), all within easy reach.
The West Midlands has a large stock of 1930s and post-war semi-detached houses, which are well suited to rear, side and over-garage extensions, plus Victorian terraces in the older inner areas.
Planning rules that apply in Birmingham
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
The planning position for a specific Birmingham address depends on its history and any designations, which is why we check it at the first visit.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
What we take care of
- Insulation, plastering, electrics and plumbing to finish
- Building regulations drawings and structural design
- Measured survey, design and planning drawings
- Ground and first floor structure, roof tied into the existing roof
- Householder planning application where needed
- Breaking through at both levels, stairs and landing changes where needed
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Your questions about a double-storey extension in Birmingham
Will my neighbours in Birmingham be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Who do I contract with for a double-storey extension in Birmingham?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do you cover all of Birmingham?
Yes. We cover Birmingham and the surrounding parts of West Midlands. Site visits are free and there is no obligation.
Is a two-storey extension cheaper per square metre?
Usually. Our guide range is about £1,500 to £2,910 per m² of new floor area including VAT, compared with £1,700 to £3,300 per m² for single-storey work, because the foundations and roof are shared across two floors.
Do I need a Party Wall Agreement?
If you are in England or Wales and the work involves a shared wall or digging foundations close to a neighbour, the Party Wall etc. Act 1996 applies and notices must be served before work starts. We tell you which notices are needed.
Book a free site visit in Birmingham
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.