Extensions over a garage in Farnborough (Greater London)

Before you start in Farnborough (Greater London), here's what applies.

Postcode districts: BR6
County / area: Greater London, England
Price region: London
Guide price: £38,000–£55,000 (£2,100–£3,060 per m²)
Approval route: Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
Nearest towns: Orpington (1.6 miles), Chelsfield (2.5 miles), Bickley (3.1 miles)
First visit: Free, no obligation

About an extension over a garage

An extension over a garage suits you if you have an attached single garage beside the house and need an extra bedroom or a larger main bedroom with an en-suite. You get an inspection of the garage structure, a design that matches the house, the approvals your nation needs, structural design, building regulations approval and the build, carried out by vetted teams working under S&K.

Around Farnborough (Greater London) we also work in Orpington, Chelsfield and Bickley, and across the rest of Greater London. Postcode district in and near Farnborough (Greater London): BR6.

What it costs in Farnborough (Greater London)

Guide prices for extensions over a garage in London are around £2,100–£3,060 per m² of new floor space, including VAT. For a typical project with 3 m × 6 m of new first-floor space (18 m²), that's roughly £38,000–£55,000. Keep a contingency of around 10% for things nobody can see until the ground is opened up.

Spec	Per m²	3 m × 6 m of new first-floor space (18 m²)
Essential	£1,930–£2,820 per m²	£35,000–£50,500
Standard	£2,100–£3,060 per m²	£38,000–£55,000
Premium	£2,520–£3,670 per m²	£45,500–£66,000

Planning and building regulations in Farnborough (Greater London)

In England, most garages sit beside the house, so building over one makes a two-storey extension beyond a side wall, which always needs planning permission. If the garage is at the rear, the 3 m and 7 m rules for two-storey rear extensions apply, measured from the original house. 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 Farnborough (Greater London) homes

Floor levels and headroom

Garage floors are often lower than the house, and the new first floor may not line up with the existing landing. We set the floor level to avoid awkward steps upstairs, while keeping enough headroom in the garage below for a car or storage.

Garage walls and the door opening

Garage walls are often a single skin of brick or block with piers, and the wide door opening needs a beam over it. Many over-garage extensions need new inner walls or a steel frame to carry the floor and to insulate properly, which we confirm before the design is fixed.

How we'd run your project

Visit and first ideas
One of our team visits your house in Farnborough (Greater London), checks the walls, roof and drains, and sketches out options with you.
Drawings and permission
Our designers produce plans and elevations, then we take care of planning or permitted development checks with the council covering Farnborough (Greater London).
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
Build and hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.

Questions about extensions over a garage in Farnborough (Greater London)

Do I need planning permission for an extension over a garage in Farnborough (Greater London)?

Farnborough (Greater London) is in England, so England planning rules apply. Planning permission is needed: in England, permitted development only allows single-storey extensions to the side. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Who handles building regulations for a project in Farnborough (Greater London)?

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 long does an extension over a garage 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.

Do I need to convert the garage as well?

No. You can keep the garage for parking or storage and build only the room above, as long as the floor between them and any door into the house meet fire separation rules. Converting the garage at the same time is often good value, because the walls and foundations may be upgraded anyway.

Can my garage take a room on top?

Sometimes, but it needs checking. Many garages are built on shallow footings with thin walls, designed only for a single storey. We dig a trial hole and inspect the walls, and the structural engineer decides whether to reuse them, strengthen them, underpin the footings or build new foundations inside the garage.

Nearby

Close to Farnborough (Greater London)? We work across the area, including:

Other extensions in Farnborough (Greater London)

All two-storey extension services in Farnborough (Greater London) · Extensions over a garage across Greater London

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