Extensions over a garage in Westhoughton
Our extensions over a garage service in Westhoughton covers everything: measured survey, design, planning or permitted development checks, structural design, building control and the build itself.
Quick reference for homeowners in Westhoughton.
- Postcode districts
- BL5
- County / area
- Greater Manchester, England
- Price region
- North West England
- Guide price
- £30,000–£43,500 (£1,660–£2,420 per m²)
- Approval route
- Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
- Nearest towns
- Atherton (2.2 miles), Hindley (2.6 miles), Tyldesley (3.4 miles)
- Distance to Manchester
- about 12.7 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.
Westhoughton sits about 12.7 miles from Manchester. Closer to home, Atherton is 2.2 miles away and Hindley 2.6 miles.
What it costs in Westhoughton
Most of the cost of an extension over a garage is set by its size and specification. For Westhoughton and the rest of North West England, our guide is £1,660–£2,420 per m² including VAT, so about £30,000–£43,500 for 3 m × 6 m of new first-floor space (18 m²). We'll give you a written design-stage price first, then a fixed build price once the drawings are agreed.
| Spec | Per m² | 3 m × 6 m of new first-floor space (18 m²) |
|---|---|---|
| Essential | £1,530–£2,230 per m² | £27,500–£40,000 |
| Standard | £1,660–£2,420 per m² | £30,000–£43,500 |
| Premium | £1,990–£2,910 per m² | £36,000–£52,500 |
Planning and building regulations in Westhoughton
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 Westhoughton 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
Free site visit
We visit your home in Westhoughton, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
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 Westhoughton
Which postcodes do you cover around Westhoughton?
We cover Westhoughton (BL5) and nearby places including Atherton, Hindley and Tyldesley, plus the rest of Greater Manchester. The first site visit is free.
Who handles building regulations for a project in Westhoughton?
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 Westhoughton?
Our guide for North West England, which covers Westhoughton, is £1,660–£2,420 per m² including VAT. A typical project with 3 m × 6 m of new first-floor space (18 m²) comes to about £30,000–£43,500. 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
We also cover places near Westhoughton, including:
Other extensions in Westhoughton
- Rear
- Side
- Wraparound
- Part two-storey
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Westhoughton · Extensions over a garage across Greater Manchester
Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.