Home office extensions in Coulsdon
Coulsdon homeowners can use us for the whole home office extension project: survey, design, planning or permitted development checks, building regulations and the build itself.
- Guide price in CoulsdonFrom £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 districtsCR5, CR8

Local to Coulsdon
We cover Coulsdon and the postcode districts CR5, CR8. Neighbouring towns we cover include Purley (2 miles), Wallington (3 miles), Sutton (3 miles), Carshalton (4 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.
Planning rules that apply in Coulsdon
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.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
Who a home office extension suits
- Households that need a second quiet room
- Homes where a loft or garden room is not practical
- People who work from home most of the week
What should I budget for a home office extension in Coulsdon?
For Coulsdon 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 Coulsdon: £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 |
For a figure based on your own dimensions, use our guide-price tool.
How the project works
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
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Common questions in Coulsdon
Who do I contract with for a home office extension in Coulsdon?
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 a home office extension take to build in Coulsdon?
On site, typically 8 to 12 weeks once approvals are in place. Before that, allow 4–10 weeks design and approvals.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Coulsdon, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Can I claim the cost against tax?
Building work on your home is not normally an allowable business expense, and claiming it can have capital gains tax effects. Speak to an accountant before assuming any tax relief.
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.
Book a free site visit in Coulsdon
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.