First-floor extensions in Bartley Green

The basics for Bartley Green at a glance.

Postcode districts: B29, B30, B31, B32, B38 and B45
County / area: West Midlands, 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: Halesowen (2.4 miles), Smethwick (4.2 miles), Oldbury (4.5 miles)
Distance to Birmingham: about 5.2 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.

Bartley Green sits about 5.2 miles from Birmingham. Closer to home, Halesowen is 2.4 miles away and Smethwick 4.2 miles.

What it costs in Bartley Green

For budgeting in Bartley Green, allow around £25,000–£36,500 for a first-floor extension with 4 m × 3.5 m of new first-floor space (14 m²). That's based on £1,800–£2,600 per m² including VAT for the West Midlands. Design fees, structural calculations and approval fees are separate and listed on our prices page.

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 Bartley Green

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 Bartley Green homes

Escape and fire safety

A new first-floor bedroom needs an escape window with a clear opening of at least 0.33 m², at least 450 mm wide and 450 mm high, with the bottom no more than 1,100 mm above the floor, unless there is a protected route to the stairs.

Replacing the flat roof

The existing roof usually comes off and is replaced by a new first-floor structure. The room below is exposed for a short time, so we plan temporary weatherproofing and sequence the work to keep the kitchen or living room usable for as long as possible.

How we'd run your project

Look at the house
We start in Bartley Green with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
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 Bartley Green

Who handles building regulations for a project in Bartley Green?

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 first-floor extension cost in Bartley Green?

Our guide for the West Midlands, which covers Bartley Green, is £1,800–£2,600 per m² including VAT. A typical project with 4 m × 3.5 m of new first-floor space (14 m²) comes to about £25,000–£36,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Which postcodes do you cover around Bartley Green?

We cover Bartley Green (B29, B30, B31, B32, B38 and B45) and nearby places including Halesowen, Smethwick and Oldbury, plus the rest of the West Midlands. The first site visit is free.

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.

Will the first-floor extension match my house?

It should, and in England matching materials and roof pitch is a condition of permitted development. We match brick, tile, mortar colour and window style where we can, and tell you at the design stage if an exact brick match is not available, so you can choose between the closest match and render or cladding.

Nearby

Nearby towns we cover for first-floor extensions:

Other extensions in Bartley Green

All two-storey extension services in Bartley Green · First-floor extensions across the West Midlands

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