East Cornwall · PL15
Design, planning and build for Tregadillett 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 PL15 plot rarely works elsewhere — Tregadillett is a commuter village in the PL15 area, with everyday family housing, edge-of-village plots and quick routes to its parent town, with a building stock that leans toward post-war semis and garden infill plots.
Tregadillett sits in East Cornwall — covering PL15 from Launceston, Warbstow, North Petherwin outward.
- Rural / open-countryside policy area
- ✓ rural policy area experience built into the fee
- ✓ 30+ years of Cornwall Council approvals
- ✓ Local to East Cornwall — not a national franchise
- ✓ Same team on paper as on site
Local proof — Most Tregadillett 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 Tregadillett is its own job.
Cornwall Council's lens on Tregadillett is consistent: applications here usually turn on neighbour amenity, parking, overlooking and whether new work fits the rhythm of existing streets. 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 Tregadillett project as a PL15-area job first — not a generic Cornwall job with a postcode bolted on. The post-war semis that dominate Tregadillett (and continue out toward North Petherwin) 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 Tregadillett.
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
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.
04
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
Our process
How a Tregadillett 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
Choosing a extension team that actually knows PL15.
Building stock
Across Tregadillett (PL15) we work on post-war semis, bungalows, modern estates, older cottages, garden infill plots. Each stock type drives a different extension response — post-war semis in particular needs careful detailing here.
Parish & policy
Tregadillett sits in the parish of Tregadillett, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover PL15 from our studio, with regular extension jobs also running in Launceston, Warbstow, North Petherwin. Most Tregadillett site visits get booked within the same week.
How quickly can you visit a Tregadillett site?
Usually within the same week. Tregadillett (PL15) is on our regular East Cornwall run, alongside Launceston, Warbstow, North Petherwin. First visits are free and you'll get an honest feasibility view inside seven days.
Request a free visitFAQs
Tregadillett 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 Tregadillett specifically, we'd start by checking the latest parish-level planning history before committing to a direction.
- 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 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.
Tregadillett is part of Launceston
Tregadillett sits inside the Launceston catchment — we cover both as one extension territory.
See Extensions in Launceston →Other services in Tregadillett
Nearby places we cover
Designing a extension in Tregadillett is as much about reading the parish as reading the brief; we do both, and the planning outcomes follow.