Mid Cornwall · TR2
Probus extension — feasibility first, drawings second
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. In Probus, that work is shaped by the place itself — Probus is a substantial inland village between Truro and St Austell, with the tallest church tower in Cornwall and a Conservation Area covering the village centre, with a building stock that leans toward Victorian terraces and modern Persimmon-style estates.
Probus sits in Mid Cornwall — covering TR2 from Grampound, Ladock, Tresillian outward.
- Conservation Area
- Rural / open-countryside policy area
- ✓ Free first site visit, no obligation
- ✓ Plain-English feasibility before any drawings
- ✓ 30+ years of Cornwall Council approvals
- ✓ Conservation Area experience built into the fee
Who this is for
Probus runs the full mix — owner-occupier, holiday-let, commercial and the occasional smallholding — so we scope every extension enquiry from the use-class up.
Local watch-list
What usually catches extension projects out in Probus.
Watch #1
Conservation Area material and fenestration controls in central Probus
Watch #2
Tighter Local Plan tests on isolated rural dwellings
Local proof — We typically have one or two extension jobs live in the TR2 area at any time, so the local planning officers know our drawings on sight.
Get a free feasibility viewFAQs
Probus Extensions — local questions answered.
- 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. In Probus specifically, we'd start by checking the Conservation Area boundary before committing to a direction.
- Do I need planning permission for an extension?
- Often no — single-storey rear extensions, side extensions and modest two-storey additions can sit inside permitted development on a typical detached house. Conservation Areas, AONB and Article 4 zones remove some of those rights, so we always check the address first.
- 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.
- 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.
Local context
Why Probus is its own job.
Locally, conservation Area covers the village core including the church. Tregothnan Estate (the largest private estate in Cornwall) lies to the south and shapes some adjacent applications. For extension specifically, parts of Probus sit within a designated Conservation Area, which means materials, fenestration and roof pitches all need to read sympathetically with the existing streetscape; 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. Which is why we scope Probus projects parish-up, not template-down — the TR2 context shapes the design from day one. Whether the project is on Victorian terraces in the centre or further out toward Grampound, the extension response is locally tuned.
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.
What we focus on
Extensions considerations specific to Probus.
01
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.
02
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
03
Wind and sea-spray exposure can drive material choices on west-facing extensions; we detail accordingly.
04
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.
Our process
How a Probus 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 fabric
Why Probus homeowners pick a local studio for extension.
Building stock
Across Probus (TR2) we work on traditional cob and granite cottages, Victorian terraces, Edwardian villas, post-war estates, modern Persimmon-style estates. Each stock type drives a different extension response — Victorian terraces in particular needs careful detailing here.
Parish & policy
Probus is its own town in Mid Cornwall, with planning history that's specific to the TR2 catchment.
Coverage
We cover TR2 from our studio, with regular extension jobs also running in Grampound, Ladock, Tresillian. Most Probus site visits get booked within the same week.
What does a first Probus consultation cost?
Nothing. We come to the property, walk the site, talk through what works on a TR2 plot and follow up with a written feasibility note inside a week — no obligation either way.
Request a free visitOther services in Probus
Nearby places we cover
The extension jobs we're proudest of in Probus are the ones where the planning route was clear before a single elevation was drawn.