West Cornwall · TR18
Design, planning and build for Chyandour extension
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. What works on a TR18 plot rarely works elsewhere — Chyandour is a harbour-side settlement in the TR18 area, with compact lanes, coastal exposure and a working-waterfront character, with a building stock that leans toward holiday flats and granite terraces.
Chyandour sits in West Cornwall — covering TR18 from Penzance, Sancreed, New Mill outward.
- Conservation Area
- Coastal exposure zone
- ✓ Conservation Area experience built into the fee
- ✓ Local to West Cornwall — not a national franchise
- ✓ Same team on paper as on site
- ✓ Fixed-fee planning packages, no surprise invoices
Local proof — Most Chyandour extension clients we work with are second-time builders — they've seen the templated approach fail once already.
Get a free feasibility viewLocal context
Why Chyandour is its own job.
Cornwall Council's lens on Chyandour is consistent: harbour settings bring tight access, overlooking, flood risk and heritage character into play on even modest alterations. For extension specifically, parts of Chyandour sit within a designated Conservation Area, which means materials, fenestration and roof pitches all need to read sympathetically with the existing streetscape; coastal salt-laden air around Chyandour drives detailing choices — fixings, render systems and timber treatments all need to be specified for exposure. That's why we treat every Chyandour project as a TR18-area job first — not a generic Cornwall job with a postcode bolted on. The holiday flats that dominate Chyandour (and continue out toward New Mill) set the tone for any extension scheme here.
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 Chyandour.
01
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
02
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.
03
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
Our process
How a Chyandour 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 Chyandour homeowners pick a local studio for extension.
Building stock
Across Chyandour (TR18) we work on harbour cottages, net lofts, granite terraces, holiday flats, steep-lane houses. Each stock type drives a different extension response — holiday flats in particular needs careful detailing here.
Parish & policy
Chyandour sits in the parish of Chyandour, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover TR18 from our studio, with regular extension jobs also running in Penzance, Sancreed, New Mill. Most Chyandour site visits get booked within the same week.
How quickly can you visit a Chyandour site?
Usually within the same week. Chyandour (TR18) is on our regular West Cornwall run, alongside Penzance, Sancreed, New Mill. First visits are free and you'll get an honest feasibility view inside seven days.
Request a free visitFAQs
Chyandour 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 Chyandour 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.
- 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 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.
Chyandour is part of Penzance
Chyandour sits inside the Penzance catchment — we cover both as one extension territory.
See Extensions in Penzance →Other services in Chyandour
Nearby places we cover
Designing a extension in Chyandour is as much about reading the parish as reading the brief; we do both, and the planning outcomes follow.