Extensions over a garage in Leatherhead: design, approvals and build
We design and build over-garage extensions for houses in Leatherhead, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in LeatherheadFrom £26,500 inc VAT
- PlanningHouseholder application needed
- Build time12–18 weeks on site
- Postcode districtsKT21, KT22, KT23
What should I budget for an over-garage extension in Leatherhead?
Labour and material costs vary across the UK, so for Leatherhead we use our South East England factor (×1.12). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Leatherhead: £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.
When an over-garage extension makes sense
- Families needing a bedroom without losing garden
- Homes where the landing can connect to the new room
- Detached and link-detached houses with an attached garage
Planning rules that apply in Leatherhead
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.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
Local to Leatherhead
Site visits are available across Leatherhead (KT21, KT22, KT23). Nearby, we also take on projects in Epsom (4 miles), Ewell (5 miles), Esher (5 miles), Banstead (6 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.
Our process, step by step
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
We visit your Leatherhead home, measure up, talk through what you want and check the planning position.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Leatherhead
Will my neighbours in Leatherhead be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Leatherhead, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Leatherhead?
Yes. We cover Leatherhead and the surrounding parts of Surrey. 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 Leatherhead
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.