Lizard Peninsula · TR12
Extensions Trelowarren: TR12 planning, Lizard Peninsula fabric
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 TR12 plot rarely works elsewhere — Trelowarren is an estate-influenced village in the TR12 area, with designed landscape, older cottages and rural edges close together, with a building stock that leans toward estate cottages and small infill plots.
Trelowarren sits in Lizard Peninsula — covering TR12 from Helston, Breage, Ashton outward.
- Cornwall AONB
- Rural / open-countryside policy area
- ✓ 30+ years of Cornwall Council approvals
- ✓ Cornwall Council regulars across every sub-area
- ✓ Measured-survey accuracy from day one
- ✓ One studio — design, planning and build under one roof
Local proof — We typically have one or two extension jobs live in the TR12 area at any time, so the local planning officers know our drawings on sight.
Get a free feasibility viewLocal context
Why Trelowarren is its own job.
Landscape setting, curtilage history and estate character need a precise design rationale rather than a standard suburban approach. That sets the scene before any design work begins. 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; 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. It's the kind of detail that decides whether a Trelowarren application gets approved at eight weeks or stalls in committee. The estate cottages that dominate Trelowarren (and continue out toward Ashton) 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 Trelowarren.
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
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 Trelowarren 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 Trelowarren homeowners pick a local studio for extension.
Building stock
Across Trelowarren (TR12) we work on estate cottages, farm buildings, detached homes, converted outbuildings, small infill plots. Each stock type drives a different extension response — estate cottages in particular needs careful detailing here.
Parish & policy
Trelowarren sits in the parish of Trelowarren, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover TR12 from our studio, with regular extension jobs also running in Helston, Breage, Ashton. Most Trelowarren site visits get booked within the same week.
How quickly can you visit a Trelowarren site?
Usually within the same week. Trelowarren (TR12) is on our regular Lizard Peninsula run, alongside Helston, Breage, Ashton. First visits are free and you'll get an honest feasibility view inside seven days.
Request a free visitFAQs
Trelowarren 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 Trelowarren specifically, we'd start by checking AONB landscape sensitivity 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.
- 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.
- 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.
Trelowarren is part of Helston
Trelowarren sits inside the Helston catchment — we cover both as one extension territory.
See Extensions in Helston →Other services in Trelowarren
Nearby places we cover
Designing a extension in Trelowarren is as much about reading the parish as reading the brief; we do both, and the planning outcomes follow.