Extensions over a garage in Salisbury

The basics for Salisbury at a glance.

Postcode districts: SP1, SP2, SP3 and SP5
County / area: Wiltshire, England
Price region: South West 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: Amesbury (7.3 miles), Bulford (8.4 miles), Tidworth (12.6 miles)
Distance to Swindon: about 33.8 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.

Salisbury sits about 33.8 miles from Swindon. Closer to home, Amesbury is 7.3 miles away and Bulford 8.4 miles.

What it costs in Salisbury

In South West England, which includes Salisbury, we'd expect an extension over a garage to cost around £32,500–£47,500 for 3 m × 6 m of new first-floor space (18 m²), or £1,800–£2,630 per m² including VAT. These are guides, not quotes. Ground conditions, steelwork and access can move the figure either way.

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 Salisbury

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 Salisbury 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.

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.

How we'd run your project

Free site visit
We visit your home in Salisbury, 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.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
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 Salisbury

Who handles building regulations for a project in Salisbury?

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 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.

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

Our guide for South West England, which covers Salisbury, 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.

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

Close to Salisbury? We work across the area, including:

Other extensions in Salisbury

All two-storey extension services in Salisbury · Extensions over a garage across Wiltshire

Tell us about your house in Salisbury and we'll call you back to arrange a free, no-obligation visit.