Mid Cornwall · TR3
Design, planning and build for Kea 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. Every Kea project we take on begins with reading the local context — Kea is a creekside settlement in the TR3 area, with waterside homes, wooded valleys and narrow-lane access shaping the brief, with a building stock that leans toward detached houses and creekside cottages.
Kea sits in Mid Cornwall — covering TR3 from Truro, St Michael Penkivel, Calenick outward.
- Rural / open-countryside policy area
- ✓ Plain-English feasibility before any drawings
- ✓ Free first site visit, no obligation
- ✓ Fixed-fee planning packages, no surprise invoices
- ✓ Measured-survey accuracy from day one
Local proof — We typically have one or two extension jobs live in the TR3 area at any time, so the local planning officers know our drawings on sight.
Get a free feasibility viewLocal context
Why Kea is its own job.
Cornwall Council's lens on Kea is consistent: creekside ecology, flood risk, trees and views across the water often matter as much as the building form itself. 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. That's why we treat every Kea project as a TR3-area job first — not a generic Cornwall job with a postcode bolted on. The detached houses that dominate Kea (and continue out toward Calenick) 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 Kea.
01
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
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 Kea 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 a Mid Cornwall studio is the right fit for Kea extension.
Building stock
Across Kea (TR3) we work on creekside cottages, detached houses, boat sheds, converted barns, waterside homes. Each stock type drives a different extension response — detached houses in particular needs careful detailing here.
Parish & policy
Kea sits in the parish of Kea, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover TR3 from our studio, with regular extension jobs also running in Truro, St Michael Penkivel, Calenick. Most Kea site visits get booked within the same week.
How quickly can you visit a Kea site?
Usually within the same week. Kea (TR3) is on our regular Mid Cornwall run, alongside Truro, St Michael Penkivel, Calenick. First visits are free and you'll get an honest feasibility view inside seven days.
Request a free visitFAQs
Kea Extensions — local questions answered.
- 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. In Kea specifically, we'd start by checking the latest parish-level planning history 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.
- 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.
- 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.
Kea is part of Truro
Kea sits inside the Truro catchment — we cover both as one extension territory.
See Extensions in Truro →Other services in Kea
Nearby places we cover
To sum up, our extension approach in Kea is built entirely around local Cornwall context, ensuring the best possible outcome for your property.