Extensions over a garage in Biggleswade

Before you start in Biggleswade, here's what applies.

Postcode districts: SG18
County / area: Bedfordshire, England
Price region: East of England
Guide price: £32,500–£47,500 (£1,800–£2,630 per m²)
Approval route: Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
Nearest towns: Sandy (3.1 miles), Henlow (4 miles), Baldock (7.6 miles)
Distance to Luton: about 15.7 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.

Biggleswade sits about 15.7 miles from Luton. Closer to home, Sandy is 3.1 miles away and Henlow 4.0 miles.

What it costs in Biggleswade

Expect an extension over a garage in Biggleswade to land somewhere around £32,500–£47,500 for 3 m × 6 m of new first-floor space (18 m²). Our East of England guide rate is £1,800–£2,630 per m², including VAT. Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.

Spec	Per m²	3 m × 6 m of new first-floor space (18 m²)
Essential	£1,660–£2,420 per m²	£30,000–£43,500
Standard	£1,800–£2,630 per m²	£32,500–£47,500
Premium	£2,160–£3,150 per m²	£39,000–£56,500

Planning and building regulations in Biggleswade

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 Biggleswade homes

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.

Checking the garage foundations

Garages are often built on shallow strip footings sized for a single-storey wall and a light roof. A trial hole shows their depth and condition, and the engineer decides whether they can carry two storeys or need underpinning or new foundations inside the garage.

How we'd run your project

Start at your house
We come to your home in Biggleswade, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in England before drawing in detail.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Questions about extensions over a garage in Biggleswade

Who handles building regulations for a project in Biggleswade?

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.

Which postcodes do you cover around Biggleswade?

We cover Biggleswade (SG18) and nearby places including Sandy, Henlow and Baldock, plus the rest of Bedfordshire. The first site visit is free.

How much does an extension over a garage cost in Biggleswade?

Our guide for the East of England, which covers Biggleswade, is £1,800–£2,630 per m² including VAT. A typical project with 3 m × 6 m of new first-floor space (18 m²) comes to about £32,500–£47,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

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.

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 Biggleswade? We work across the area, including:

Other extensions in Biggleswade

All two-storey extension services in Biggleswade · Extensions over a garage across Bedfordshire

Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.