Mid Cornwall · PL26
One studio for extension in Coombe St Austell
Extensions are the bread and butter of Cornish homes — adding the kitchen-diner the original layout never had, the bedroom for a growing family, or the light and views the back of the house should always have had. Coombe St Austell sits in Mid Cornwall, and that geography ends up in the drawings — Coombe St Austell is a small rural hamlet in the PL26 area, with scattered homes, lanes and a deliberately quiet settlement pattern, with a building stock that leans toward farmhouses and bungalows.
Coombe St Austell sits in Mid Cornwall — covering PL26 from St Austell, Bugle, St Dennis outward.
- Rural / open-countryside policy area
- ✓ One studio — design, planning and build under one roof
- ✓ Local to Mid Cornwall — not a national franchise
- ✓ Fixed-fee planning packages, no surprise invoices
- ✓ Measured-survey accuracy from day one
Our process
How a Coombe St Austell extension project runs.
Step 1
Brief
We meet on site, talk through how you live now and what's missing from the current layout.
Step 2
Design
Two or three sketch directions with rough budgets, then refinement of the chosen route.
Step 3
Approvals
Planning or Cert of Lawfulness, then a full building regs package.
Step 4
Build
Either through your own builder with our drawings, or as a full build by our team.
Step 5
Handover
Snag, certify, hand over the keys to your new space.
Typical single-storey rear extensions run twelve to twenty weeks on site; two-storey and wraparound projects sixteen to thirty weeks.
Local proof — Most Coombe St Austell extension clients we work with are second-time builders — they've seen the templated approach fail once already.
Get a free feasibility viewWhat we focus on
Extensions considerations specific to Coombe St Austell.
01
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
02
Permitted development for rear extensions runs to four metres on a detached house, three on a semi or terrace — but Article 4 areas remove this in some parishes.
03
Extensions over a certain proportion of the original house trigger full Part L upgrade obligations to the existing building — worth knowing before brief is set.
04
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
Local context
Why Coombe St Austell is its own job.
Two things shape a Coombe St Austell application: parish character and policy. On policy — the main planning test is usually whether the proposal remains subordinate, locally detailed and acceptable on access, drainage and neighbour amenity. For extension specifically, Cornwall Council's Local Plan applies tighter tests to isolated rural dwellings here, so design rationale and policy fit need to be set out clearly from the outset. Get that local reading right and the rest of the Coombe St Austell programme tends to run on time. On farmhouses in particular — the kind you'll also find toward Nanpean — the extension brief always has to read the existing fabric first.
Planning note
Most extensions in Cornwall are either permitted development or a straightforward householder application — but Conservation Area and AONB sites need a more careful design conversation upfront.
Local watch-list
What usually catches extension projects out in Coombe St Austell.
Watch #1
Tighter Local Plan tests on isolated rural dwellings
Coombe St Austell is part of St Austell
Coombe St Austell sits inside the St Austell catchment — we cover both as one extension territory.
See Extensions in St Austell →Local fabric
One PL26 studio, one extension job — start to finish.
Building stock
Across Coombe St Austell (PL26) we work on cottages, farmhouses, converted barns, bungalows, small infill homes. Each stock type drives a different extension response — farmhouses in particular needs careful detailing here.
Parish & policy
Coombe St Austell sits in the parish of Coombe St Austell, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover PL26 from our studio, with regular extension jobs also running in St Austell, Bugle, St Dennis. Most Coombe St Austell site visits get booked within the same week.
Can you handle both planning and build in Coombe St Austell?
Yes — design, planning, building regs and full construction run under one roof. For clients with an existing Coombe St Austell builder we can stop at a tender-ready Full Plans pack instead.
Request a free visitWho this is for
Coombe St Austell runs the full mix — owner-occupier, holiday-let, commercial and the occasional smallholding — so we scope every extension enquiry from the use-class up.
FAQs
Coombe St Austell Extensions — local questions answered.
- What about the Party Wall Act?
- If you share a wall with a neighbour or build close to a boundary, the Act applies. We flag it early, recommend a surveyor and keep the programme aligned with the notice period. In Coombe St Austell specifically, we'd start by checking the latest parish-level planning history before committing to a direction.
- How much does an extension cost in Cornwall?
- Build costs in Cornwall typically run from around £2,200 to £3,200 per square metre for a good-quality single-storey extension, more for kitchen-grade fit-out or complex glazing. We give a realistic budget before drawings start, not after.
- Can you handle the build as well as the design?
- Yes — that's the whole point of the studio. One contract, one point of contact, no finger-pointing between architect and builder when something needs a decision on site.
- Will my house be liveable during the build?
- For most rear and side extensions, yes — we sequence the works so the kitchen and one bathroom stay functional until the new build is watertight and connected.
- How long does the whole process take?
- Allow roughly three months for design and approvals, then twelve to twenty weeks on site for a typical single-storey extension. Wraparounds and two-storey add-ons take longer, mostly through approval and groundworks.
Other services in Coombe St Austell
Nearby places we cover
Every Coombe St Austell extension we work on is treated as a PL26 job in its own right — local fabric, local policy, local builders.