Home office extensions across St Austell
Planning a home office extension in St Austell? 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 St AustellFrom £16,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–12 weeks on site
- Postcode districtsPL25
How much does a home office extension cost in St Austell?
Prices below are for St Austell, using the South West England factor of ×1.02. They are guide ranges including VAT for the build only, not a quote.
Typical rates in St Austell: £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 |
For a figure based on your own dimensions, use our guide-price tool.
Local to St Austell
Postcode districts we cover around St Austell include PL25. The same team covers Bodmin (9 miles), Truro (13 miles), Newquay (14 miles), Falmouth (18 miles), all within easy reach.
Just over the Devon border, Plymouth is about 28 miles away. South West homes range from terraced streets in the cities to stone cottages and bungalows in the countryside, and conservation areas are common in historic centres.
Will the council need to approve it?
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.
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.
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 is included
- Window and rooflight placement to avoid screen glare
- Data cabling and plenty of sockets
- Layout for desk, storage and video calls
- Heating or cooling sized for the room
- Sound insulation to the adjoining rooms
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.
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
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
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Common questions in St Austell
Do you cover all of St Austell?
Yes. We cover St Austell and the surrounding parts of Cornwall. Site visits are free and there is no obligation.
Will my neighbours in St Austell 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.
How long does a home office extension take to build in St Austell?
On site, typically 8 to 12 weeks once approvals are in place. Before that, allow 4–10 weeks design and approvals.
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.
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 St Austell.
Book a free site visit in St Austell
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.