Extensions over a garage for homes in Egham
From the first sketch to final sign-off, we plan and build over-garage extensions in Egham and the surrounding Surrey area.
- Guide price in EghamFrom £26,500 inc VAT
- PlanningHouseholder application needed
- Build time12–18 weeks on site
- Postcode districtsGU25, TW18, TW20
Extensions in and around Egham
Site visits are available across Egham (GU25, TW18, TW20). Neighbouring towns we cover include Staines-upon-Thames (2 miles), Ashford, Surrey (4 miles), Weybridge (6 miles), Sunbury-on-Thames (6 miles).
For homes towards Berkshire, Windsor is around 4 miles away. The South East has a broad mix of 1930s semis, post-war estates, newer developments and period cottages, and many houses have enough garden for a generous rear extension.
How much does an over-garage extension cost in Egham?
Prices below are for Egham, 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 Egham: £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 |
For a figure based on your own dimensions, use our guide-price tool.
Will the council need to approve it?
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.
The planning position for a specific Egham address depends on its history and any designations, which is why we check it at the first visit.
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).
Is an over-garage extension right for your house?
- Homes where the landing can connect to the new room
- Detached and link-detached houses with an attached garage
- Families needing a bedroom without losing garden
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.
What happens next
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 Egham home, measure up, talk through what you want and check the planning position.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
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.
Your questions about an over-garage extension in Egham
Do you cover all of Egham?
Yes. We cover Egham and the surrounding parts of Surrey. Site visits are free and there is no obligation.
Who do I contract with for an over-garage extension in Egham?
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.
How long does an over-garage extension take to build in Egham?
On site, typically 12 to 18 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
Does building over a garage need planning permission?
In England and the rest of the UK, adding a storey over a side garage almost always needs a planning application, because two-storey side extensions are outside permitted development.
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.
Book a free site visit in Egham
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.