Extensions over a garage in Ascot

Ascot: the key facts for this kind of project.

Postcode districts: SL5
County / area: Berkshire, England
Price region: South East England
Guide price: £34,500–£50,500 (£1,930–£2,800 per m²)
Approval route: Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
Nearest towns: Sunninghill (1.1 miles), Bracknell (3.3 miles), Egham (5.5 miles)
Distance to Reading: about 13.1 miles
First visit: Free, no obligation

About an extension over a garage

An extension over a garage is a new first-floor room built on top of an existing attached garage, usually a bedroom, en-suite or study. It uses a footprint you already have, so it adds floor space without taking any garden. The garage walls and foundations often need strengthening or replacing to carry the new floor.

Around Ascot we also work in Sunninghill, Bracknell and Egham, and across the rest of Berkshire. Postcode district in and near Ascot: SL5.

What it costs in Ascot

Using our South East England rates, an extension over a garage with 3 m × 6 m of new first-floor space (18 m²) comes to about £34,500–£50,500, including VAT. Bigger or more glazed designs cost more per m². The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.

Spec	Per m²	3 m × 6 m of new first-floor space (18 m²)
Essential	£1,770–£2,580 per m²	£32,000–£46,500
Standard	£1,930–£2,800 per m²	£34,500–£50,500
Premium	£2,310–£3,370 per m²	£41,500–£60,500

Planning and building regulations in Ascot

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 Ascot homes

Matching the house

A room over a garage usually sits beside the front of the house in full view, so roof form, ridge height, windows and brick matter. Setting the front wall and ridge back slightly from the main house usually helps it look as if it belongs.

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.

How we'd run your project

Measure and listen
A visit to Ascot to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Get it approved
Once you're happy with the design we submit it to the council for Ascot and deal with any questions from the planning officer.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.

Questions about extensions over a garage in Ascot

Which postcodes do you cover around Ascot?

We cover Ascot (SL5) and nearby places including Sunninghill, Bracknell and Egham, plus the rest of Berkshire. The first site visit is free.

Who handles building regulations for a project in Ascot?

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 an extension over a garage cost in Ascot?

Our guide for South East England, which covers Ascot, is £1,930–£2,800 per m² including VAT. A typical project with 3 m × 6 m of new first-floor space (18 m²) comes to about £34,500–£50,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

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.

Can I add an en-suite above the garage?

Yes, and it is a common choice for a main bedroom. The en-suite needs an extract fan under Part F, a route for the soil pipe down to the drains and enough fall for the waste, which can be harder over a garage. We plan the pipe route through the garage or an outside wall early.

Nearby

Nearby towns we cover for extensions over a garage:

Other extensions in Ascot

All two-storey extension services in Ascot · Extensions over a garage across Berkshire

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