Two-storey side extensions in Bromley

Bromley: the key facts for this kind of project.

Postcode districts: BR1
County / area: Greater London, England
Price region: London
Guide price: £103,500–£138,500 (£2,460–£3,300 per m²)
Approval route: Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
Nearest towns: Shortlands (0.6 miles), Bickley (1.4 miles), Beckenham (1.7 miles)
First visit: Free, no obligation

About a two-storey side extension

A two-storey side extension is a new two-floor addition built into the space beside your house, often over a driveway or side passage. It typically adds one or two bedrooms upstairs and a utility, study or larger kitchen below, without giving up rear garden.

Around Bromley we also work in Shortlands, Bickley and Beckenham, and across the rest of Greater London. Postcode district in and near Bromley: BR1.

What it costs in Bromley

In London, which includes Bromley, we'd expect a two-storey side extension to cost around £103,500–£138,500 for a 3 m × 7 m footprint on two floors (42 m² of new floor space), or £2,460–£3,300 per m² including VAT. Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.

Spec	Per m²	A 3 m × 7 m footprint on two floors (42 m² of new floor space)
Essential	£2,260–£3,040 per m²	£95,000–£127,500
Standard	£2,460–£3,300 per m²	£103,500–£138,500
Premium	£2,950–£3,960 per m²	£124,000–£166,500

Planning and building regulations in Bromley

In England, a two-storey side extension always needs householder planning permission, because permitted development only allows single-storey extensions beyond a side wall. The fee is £548 (or £575 for applications made from 8 December 2026), and councils should decide within 8 weeks of validation. Expect them to look at set-back, roof height, gaps to the boundary and the effect on neighbours.

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 Bromley homes

Matching the ridge and roof

A hipped house usually needs a hipped extension roof, and a gabled house a gable. Matching the pitch, tiles, ridge detail and brick bond is what makes a side extension look original rather than added, and councils look closely at it on a front-facing addition.

Avoiding a terracing effect

Where semi-detached houses sit close together, side extensions on neighbouring houses can join up and turn a row of pairs into a terrace. Many councils ask for a gap to the boundary at first floor to stop this, so we check local guidance before fixing the width.

How we'd run your project

Start at your house
We come to your home in Bromley, 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 Bromley and deal with any questions from the planning officer.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.

Questions about two-storey side extensions in Bromley

How long does a two-storey side 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 Bromley?

We cover Bromley (BR1) and nearby places including Shortlands, Bickley and Beckenham, plus the rest of Greater London. The first site visit is free.

Who handles building regulations for a project in Bromley?

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 two-storey side extension cost in Bromley?

Our guide for London, which covers Bromley, is £2,460–£3,300 per m² including VAT. A typical project with a 3 m × 7 m footprint on two floors (42 m² of new floor space) comes to about £103,500–£138,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Can I build a two-storey side extension over my driveway?

Yes, if the drive is wide enough for a useful room and the council accepts the design. You may lose off-road parking, which some councils weigh up, and the foundations need to suit the ground below. We check parking, drains and meter positions at the free site visit before any drawings are prepared.

Nearby

Close to Bromley? We work across the area, including:

Other extensions in Bromley

All two-storey extension services in Bromley · Two-storey side extensions across Greater London

Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in Bromley.