Home office extensions in Cornwall
We design and build home office extensions for houses in Cornwall, with a written price once the survey and design are done and one point of contact throughout.
- Guide priceFrom £16,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Towns covered9
- Site visitFree, no obligation
Extensions in and around Cornwall
Towns we cover in Cornwall include Redruth, Falmouth, St Austell, Truro, Camborne, Newquay, Penzance, Bodmin. In the South West, local stone, render and brick vary from town to town, so matching materials is a big part of designing an extension that looks right.
Planning and approvals in Cornwall
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.
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).
What should I budget for a home office extension in Cornwall?
For Cornwall we adjust our national guide rates by ×1.02, the factor we use for South West England. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Cornwall: £1,890 to £3,470 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 3.2 m 8 m² | £16,000 – £19,500 | £17,500 – £22,500 | £22,000 – £28,000 |
| 3 m × 3.6 m 11 m² | £20,500 – £25,000 | £24,000 – £30,500 | £30,000 – £38,500 |
| 3 m × 5 m 15 m² | £28,000 – £34,000 | £32,500 – £41,500 | £41,000 – £52,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
What is included
- Window and rooflight placement to avoid screen glare
- Heating or cooling sized for the room
- Data cabling and plenty of sockets
- Sound insulation to the adjoining rooms
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 Cornwall home, measure up, talk through what you want and check the planning position.
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
The build is managed from start to finish, inspected at each stage and signed off on completion.
Common questions in Cornwall
Do you cover all of Cornwall?
Yes, across the whole of Cornwall. Site visits are free and there is no obligation.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Cornwall, 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 home office extension take to build in Cornwall?
On site, typically 8 to 12 weeks once approvals are in place. Before that, allow 4–10 weeks design and approvals.
How much does a home office extension cost?
Our guide range is about £1,890 to £3,470 per m² including VAT. An 11 m² standard-spec office is typically £24,000 to £30,500 in Cornwall.
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.
Book a free site visit in Cornwall
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.