Mid Cornwall · TR2
Tresillian extensions — a Mid Cornwall studio
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 Tresillian, that work is shaped by the place itself — Tresillian is a village east of Truro at the head of the Tresillian River, AONB-designated, with a Conservation Area covering the village core, with a building stock that leans toward post-war bungalows and modern AONB-sensitive infill.
Tresillian sits in Mid Cornwall — covering TR2 from Truro, Tregony, Ladock outward.
- Conservation Area
- Cornwall AONB
- Coastal exposure zone
- Rural / open-countryside policy area
- ✓ 30+ years of Cornwall Council approvals
- ✓ Conservation Area experience built into the fee
- ✓ Free first site visit, no obligation
- ✓ Measured-survey accuracy from day one
Who this is for
Tresillian 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 Tresillian.
Watch #1
Conservation Area material and fenestration controls in central Tresillian
Watch #2
AONB landscape-impact scrutiny on visible elevations
Watch #3
Coastal exposure driving fixing, render and joinery spec
Watch #4
Tighter Local Plan tests on isolated rural dwellings
Local proof — Most Tresillian homeowners come to us after a extension quote elsewhere felt vague on planning — we lead with feasibility instead.
Get a free feasibility viewFAQs
Tresillian Extensions — local questions answered.
- 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. In Tresillian specifically, we'd start by checking the Conservation Area boundary before committing to a direction.
- 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.
- 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 Tresillian is its own job.
The planning backdrop in Mid Cornwall is real, not abstract: conservation Area covers the village; AONB across the parish. Riverside ecology and views shape applications on the southern edge. For extension specifically, parts of Tresillian sit within a designated Conservation Area, which means materials, fenestration and roof pitches all need to read sympathetically with the existing streetscape; the surrounding landscape falls inside the Cornwall Area of Outstanding Natural Beauty, so massing, height and landscape impact carry extra weight in any planning decision; coastal salt-laden air around Tresillian drives detailing choices — fixings, render systems and timber treatments all need to be specified for exposure; 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. Treat the TR2 parish brief as the design brief and the Tresillian application has somewhere to land. Whether the project is on post-war bungalows in the centre or further out toward Truro, 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 Tresillian.
01
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
02
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
03
Wind and sea-spray exposure can drive material choices on west-facing extensions; we detail accordingly.
04
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.
Our process
How a Tresillian 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 Tresillian homeowners pick a local studio for extension.
Building stock
Across Tresillian (TR2) we work on traditional cob and granite cottages, Victorian villas, Edwardian houses, post-war bungalows, modern AONB-sensitive infill. Each stock type drives a different extension response — post-war bungalows in particular needs careful detailing here.
Parish & policy
Tresillian sits in the parish of St Erme, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover TR2 from our studio, with regular extension jobs also running in Truro, Tregony, Ladock. Most Tresillian site visits get booked within the same week.
What does a first Tresillian 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 visitTresillian is part of Truro
Tresillian sits inside the Truro catchment — we cover both as one extension territory.
See Extensions in Truro →Other services in Tresillian
Nearby places we cover
The extension jobs we're proudest of in Tresillian are the ones where the planning route was clear before a single elevation was drawn.