Extensions over a garage in Knowle
Our extensions over a garage service in Knowle covers everything: measured survey, design, planning or permitted development checks, structural design, building control and the build itself.
Before you start in Knowle, here's what applies.
- Postcode districts
- B93
- County / area
- West Midlands, England
- Price region
- West Midlands
- Guide price
- £31,500–£46,000 (£1,750–£2,550 per m²)
- Approval route
- Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
- Nearest towns
- Solihull (2.9 miles), Shirley (West Midlands) (4.1 miles), Acocks Green (5.8 miles)
- Distance to Birmingham
- about 9.8 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.
We cover postcode district B93 in and around Knowle, along with neighbouring Solihull, Shirley (West Midlands) and Acocks Green.
What it costs in Knowle
A guide price for Knowle: around £31,500–£46,000 for 3 m × 6 m of new first-floor space (18 m²). That works out at £1,750–£2,550 per m² of new floor space, including VAT at 20%. Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.
| Spec | Per m² | 3 m × 6 m of new first-floor space (18 m²) |
|---|---|---|
| Essential | £1,610–£2,350 per m² | £29,000–£42,000 |
| Standard | £1,750–£2,550 per m² | £31,500–£46,000 |
| Premium | £2,100–£3,060 per m² | £38,000–£55,000 |
Planning and building regulations in Knowle
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 Knowle 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.
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.
How we'd run your project
Look at the house
We start in Knowle with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Design and approvals
We draw the extension and check it against the rules for England, then apply for planning permission or a certificate of lawfulness, whichever fits.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.
Questions about extensions over a garage in Knowle
How much does an extension over a garage cost in Knowle?
Our guide for the West Midlands, which covers Knowle, is £1,750–£2,550 per m² including VAT. A typical project with 3 m × 6 m of new first-floor space (18 m²) comes to about £31,500–£46,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
Which postcodes do you cover around Knowle?
We cover Knowle (B93) and nearby places including Solihull, Shirley (West Midlands) and Acocks Green, plus the rest of the West Midlands. The first site visit is free.
Do I need planning permission for an extension over a garage in Knowle?
Knowle 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.
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.
How do I get into a room over the garage?
Usually through a new opening off the existing landing or a bedroom, so the stairs stay where they are. If the floor levels do not match, a step or two may be needed inside the new room. Where a landing opening is not practical, a new stair from a converted garage is an option.
Nearby
We also cover places near Knowle, including:
Other extensions in Knowle
- Rear
- Side
- Wraparound
- Part two-storey
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Knowle · Extensions over a garage across the West Midlands
Tell us about your house in Knowle and we'll call you back to arrange a free, no-obligation visit.