Extensions over a garage in Ruislip: design, approvals and build
Thinking about an over-garage extension for your Ruislip home? Start with a free site visit: we measure up, check what the council will allow and give you honest guide figures on the day.
- Guide price in RuislipFrom £31,000 inc VAT
- PlanningHouseholder application needed
- Build time12–18 weeks on site
- Postcode districtsHA4, HA5, UB10
Guide prices for Ruislip
For Ruislip we adjust our national guide rates by ×1.3, the factor we use for London. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Ruislip: £2,340 to £4,420 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Over a single garage 12 m² | £31,000 – £38,500 | £32,500 – £42,500 | £42,000 – £53,500 |
| Over a large single garage 16 m² | £37,000 – £46,000 | £43,500 – £56,500 | £56,000 – £71,000 |
| Over a double garage 24 m² | £56,000 – £69,000 | £65,500 – £84,500 | £84,000 – £106,500 |
Try the guide-price tool to see a range for your own size and finish.
Local to Ruislip
We cover Ruislip and the postcode districts HA4, HA5, UB10. The same team covers South Ruislip (1 mile), Pinner (2 miles), Northolt (3 miles), Uxbridge (3 miles), all within easy reach.
Just over the Hertfordshire border, Rickmansworth is about 5 miles away. London's housing is dominated by Victorian and Edwardian terraces, many with a rear outrigger and a side return, and 1930s semis in the outer boroughs. Conservation areas are common, so the planning check comes first.
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.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
Included in a typical project
- Opening into the existing first floor
- Design and householder planning application
- Structural survey of garage walls and foundations
- New floor structure, walls and roof
- Strengthening or rebuilding the garage walls if needed
- Insulation, electrics, heating and finish
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
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
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Your questions about an over-garage extension in Ruislip
Do I need building regulations approval in Ruislip?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Will my neighbours in Ruislip 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.
How long does an over-garage extension take to build in Ruislip?
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 £2,340 to £4,420 per m² including VAT. A single-garage room of about 12 m² usually costs £32,500 to £42,500 at standard spec, more if the garage needs rebuilding.
Book a free site visit in Ruislip
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.