Home office extensions in Carshalton: design, approvals and build
Planning a home office extension in Carshalton? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in CarshaltonFrom £20,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–12 weeks on site
- Postcode districtsSM1, SM2, SM3, SM4, SM5
Do I need planning permission 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.
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).
What should I budget for a home office extension in Carshalton?
Prices below are for Carshalton, using the London factor of ×1.3. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Carshalton: £2,400 to £4,420 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 3.2 m 8 m² | £20,500 – £25,000 | £22,000 – £28,500 | £28,000 – £35,500 |
| 3 m × 3.6 m 11 m² | £26,000 – £31,500 | £30,500 – £39,000 | £38,500 – £49,000 |
| 3 m × 5 m 15 m² | £36,000 – £43,000 | £41,500 – £53,000 | £52,500 – £66,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
What we take care of
- Layout for desk, storage and video calls
- Sound insulation to the adjoining rooms
- Heating or cooling sized for the room
- Window and rooflight placement to avoid screen glare
- Data cabling and plenty of sockets
North-facing glass and rooflights give steadier light for screen work. Where the office faces south, we use deeper reveals or external shading to keep glare and heat down.
Working in Carshalton
Site visits are available across Carshalton (SM1, SM2, SM3, SM4, SM5, SM6). We also work in nearby Wallington (1 mile), Sutton (2 miles), Mitcham (2 miles), Morden (2 miles).
In London, space is at a premium and gardens are often short, so side returns, wraparounds and carefully planned rear extensions tend to make the most of every metre.
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
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions people ask about home office extensions
How long does a home office extension take to build in Carshalton?
On site, typically 8 to 12 weeks once approvals are in place. Before that, allow 4–10 weeks design and approvals.
Who do I contract with for a home office 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 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.
Is an attached office better than a garden office?
An attached office shares the house heating and broadband, adds floor area to the home, and needs no garden path in the rain. A garden building can be cheaper and quicker but is a separate structure.
How much does a home office extension cost?
Our guide range is about £2,400 to £4,420 per m² including VAT. An 11 m² standard-spec office is typically £30,500 to £39,000 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.