Utility and boot room extensions for homes in Barnes
A utility room extension in Barnes starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in BarnesFrom £18,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time6–10 weeks on site
- Postcode districtsSW13, SW14, SW15, TW9, W4

Do I need planning permission in Barnes?
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
The planning position for a specific Barnes address depends on its history and any designations, which is why we check it at the first visit.
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.
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).
When a utility room extension makes sense
- Kitchens that have run out of space for appliances
- Busy family homes
- Houses with a side passage or small rear corner
Working in Barnes
Site visits are available across Barnes (SW13, SW14, SW15, TW9, W4, W6). Neighbouring towns we cover include Chiswick (1 mile), Roehampton (2 miles), Putney (2 miles), Fulham (2 miles).
For homes towards Surrey, East Molesey is around 7 miles away. Across London, terraced houses with narrow side returns and tight access are the norm, which shapes everything from party wall notices to how materials reach the back garden.
Guide prices for Barnes
Labour and material costs vary across the UK, so for Barnes we use our London factor (×1.3). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Barnes: £2,470 to £4,550 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2 m × 2.5 m 5 m² | £18,000 – £22,000 | £18,000 – £23,000 | £18,000 – £23,000 |
| 2.5 m × 3.2 m 8 m² | £19,500 – £23,500 | £23,000 – £29,500 | £29,000 – £36,500 |
| 3 m × 3.6 m 11 m² | £27,000 – £32,500 | £32,000 – £40,500 | £40,000 – £50,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
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
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
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
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Utility room extension questions answered
Will my neighbours in Barnes 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 Barnes, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How long does a utility room extension take to build in Barnes?
On site, typically 6 to 10 weeks once approvals are in place. Before that, allow 4–10 weeks design and approvals.
Can a utility have a toilet?
Yes, space permitting. A WC needs drainage and extraction, which we plan into the design.
How much does a utility room extension cost?
Our guide range is about £2,470 to £4,550 per m² including VAT, with a minimum of around £18,500. An 8 m² standard-spec utility is typically £23,000 to £29,500 in Barnes.
Book a free site visit in Barnes
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.