Extensions over a garage for homes in Winchester
Planning an over-garage extension in Winchester? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in WinchesterFrom £26,500 inc VAT
- PlanningHouseholder application needed
- Build time12–18 weeks on site
- Postcode districtsSO21, SO22, SO23
Covering Winchester
Site visits are available across Winchester (SO21, SO22, SO23). Nearby, we also take on projects in Eastleigh (7 miles), Southampton (12 miles), Totton (13 miles), Andover (13 miles).
In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
Planning and approvals in Winchester
In England any side extension over one storey, including a room built over a side garage, needs a householder planning application. The fee is £548 from 1 April 2026 and councils aim to decide within 8 weeks.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
What should I budget for an over-garage extension in Winchester?
Prices below are for Winchester, using the South East England factor of ×1.12. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Winchester: £2,020 to £3,810 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Over a single garage 12 m² | £26,500 – £33,000 | £28,000 – £36,500 | £36,000 – £46,000 |
| Over a large single garage 16 m² | £32,000 – £39,500 | £37,500 – £48,500 | £48,000 – £61,000 |
| Over a double garage 24 m² | £48,000 – £59,500 | £56,000 – £73,000 | £72,500 – £91,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
Included in a typical project
- New floor structure, walls and roof
- Strengthening or rebuilding the garage walls if needed
- Opening into the existing first floor
- Structural survey of garage walls and foundations
- Insulation, electrics, heating and finish
Fitting the new room to the existing landing is the planning puzzle inside the house. We design the connection first, then the roof, so the extension does not end up with awkward steps or a corridor through a bedroom.
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions people ask about over-garage extensions
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Winchester, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Who do I contract with for an over-garage extension in Winchester?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do you cover all of Winchester?
Yes. We cover Winchester and the surrounding parts of Hampshire. Site visits are free and there is no obligation.
How much does a room over a garage cost?
Our guide range is about £2,020 to £3,810 per m² including VAT. A single-garage room of about 12 m² usually costs £28,000 to £36,500 at standard spec, more if the garage needs rebuilding.
Can I keep using the garage during the build?
Usually not for parking. The garage roof is removed and the space below is used for access and props for part of the build.
Book a free site visit in Winchester
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.