Utility and boot room extensions for homes in Carshalton
Carshalton homeowners can use us for the whole utility room extension project: survey, design, planning or permitted development checks, building regulations and the build itself.
- Guide price in CarshaltonFrom £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 districtsSM1, SM2, SM3, SM4, SM5

How much does a utility room extension cost in Carshalton?
For Carshalton 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 Carshalton: £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 |
Try the guide-price tool to see a range for your own size and finish.
Planning rules that apply in Carshalton
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.
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.
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
- Busy family homes
- Houses with a side passage or small rear corner
- Kitchens that have run out of space for appliances
A good utility works like a back-of-house corridor: in from the garden, boots off, coats on hooks, washing on the way through. We plan the door positions so it doesn't become another room to walk around.
Local to Carshalton
Site visits are available across Carshalton (SM1, SM2, SM3, SM4, SM5, SM6). The same team covers Wallington (1 mile), Sutton (2 miles), Mitcham (2 miles), Morden (2 miles), all within easy reach.
Banstead, in Surrey, is roughly 4 miles from Carshalton and also on our list. 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.
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 Carshalton 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
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Utility room extension questions answered
Who do I contract with for a utility room extension in Carshalton?
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 Carshalton?
Yes. We cover Carshalton and the surrounding parts of Greater London. Site visits are free and there is no obligation.
Do I need building regulations approval in Carshalton?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Does a utility extension need planning permission?
Often not, if it is single storey and within permitted development limits. We check this for your property.
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 Carshalton.
Book a free site visit in Carshalton
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.