North Cornwall · PL28
Extensions that reads Treyarnon properly
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. A Treyarnon brief starts on the street, not the screen — Treyarnon is a holiday-coast settlement in the PL28 area, with strong second-home demand and exposed coastal building conditions, with a building stock that leans toward holiday lets and detached houses.
Treyarnon sits in North Cornwall — covering PL28 from Padstow, St Eval, Trevone outward.
- Cornwall AONB
- Coastal exposure zone
- ✓ Measured-survey accuracy from day one
- ✓ One studio — design, planning and build under one roof
- ✓ Local to North Cornwall — not a national franchise
- ✓ Same team on paper as on site
Local watch-list
Common Treyarnon pitfalls we plan around.
Watch #1
AONB landscape-impact scrutiny on visible elevations
Watch #2
Coastal exposure driving fixing, render and joinery spec
Who this is for
Treyarnon 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 context
Why Treyarnon is its own job.
Around Treyarnon (PL28), planning scrutiny often focuses on visual impact, occupancy, parking, overlooking and whether replacement buildings respect the coastal edge. For extension specifically, 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 Treyarnon drives detailing choices — fixings, render systems and timber treatments all need to be specified for exposure. Reading Treyarnon properly up front saves more time than any drawing tool ever will. Most of our extension work in Treyarnon lands on holiday lets, with detailing that has to nod to the wider St Eval streetscape.
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 Treyarnon.
01
Wind and sea-spray exposure can drive material choices on west-facing extensions; we detail accordingly.
02
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
03
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
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 Treyarnon 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.
FAQs
Treyarnon 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 Treyarnon specifically, we'd start by checking AONB landscape sensitivity 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.
- 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.
- 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.
Treyarnon is part of Padstow
Treyarnon sits inside the Padstow catchment — we cover both as one extension territory.
See Extensions in Padstow →Local proof — Our North Cornwall workload means a Treyarnon extension project never has to wait for an out-of-county team to drive down.
Get a free feasibility viewOther services in Treyarnon
Nearby places we cover
For Treyarnon homeowners weighing up a extension, the right starting point is honest feasibility — that's what we lead with, before any drawings.