Extensions over a garage in Billericay
For an extension over a garage in Billericay, the first questions are always the same: how big, which approvals, and what it will cost. This page answers all three for Essex.
Quick reference for homeowners in Billericay.
- Postcode districts
- CM4, CM11 and CM12
- County / area
- Essex, 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
- Basildon (4.5 miles), Wickford (4.6 miles), Brentwood (4.9 miles)
- Distance to Southend-on-Sea
- about 14.1 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.
We cover Billericay (CM4, CM11 and CM12) and the places around it, including Basildon (4.5 miles), Wickford (4.6 miles) and Brentwood.
What it costs in Billericay
Guide prices for extensions over a garage in the East of England are around £1,800–£2,630 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 £32,500–£47,500. 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 Billericay
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 Billericay 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.
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 Billericay, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Get it approved
Once you're happy with the design we submit it to the council for Billericay 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 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 Billericay
How much does an extension over a garage cost in Billericay?
Our guide for the East of England, which covers Billericay, 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.
Which postcodes do you cover around Billericay?
We cover Billericay (CM4, CM11 and CM12) and nearby places including Basildon, Wickford and Brentwood, plus the rest of Essex. The first site visit is free.
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.
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.
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.
Nearby
The same service in neighbouring towns:
Other extensions in Billericay
- Rear
- Side
- Wraparound
- Part two-storey
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Billericay · Extensions over a garage across Essex
Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.