East Cornwall · PL30
Design, planning and build for St Mabyn 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 PL30 plot rarely works elsewhere — St Mabyn is a substantial inland village south-east of Wadebridge, with a fifteenth-century church and a tight Conservation Area at its core, with a building stock that leans toward post-war bungalows and Edwardian houses.
St Mabyn sits in East Cornwall — covering PL30 from Wadebridge outward.
- Conservation Area
- Rural / open-countryside policy area
- ✓ Conservation Area experience built into the fee
- ✓ Measured-survey accuracy from day one
- ✓ One studio — design, planning and build under one roof
- ✓ Local to East Cornwall — not a national franchise
Local proof — Recent extension enquiries from St Mabyn have clustered around post-war bungalows — we know the route through Cornwall Council on these.
Get a free feasibility viewLocal context
Why St Mabyn is its own job.
Cornwall Council's lens on St Mabyn is consistent: conservation Area covers the village core including the church. Active parish council with detailed input on edge-of-village schemes. For extension specifically, parts of St Mabyn sit within a designated Conservation Area, which means materials, fenestration and roof pitches all need to read sympathetically with the existing streetscape; 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 St Mabyn project as a PL30-area job first — not a generic Cornwall job with a postcode bolted on. The post-war bungalows that dominate St Mabyn (and continue out toward Wadebridge) 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 St Mabyn.
01
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.
02
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
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 St Mabyn 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 East Cornwall studio is the right fit for St Mabyn extension.
Building stock
Across St Mabyn (PL30) we work on traditional granite cottages, Victorian villas, Edwardian houses, post-war bungalows, modern small estates. Each stock type drives a different extension response — post-war bungalows in particular needs careful detailing here.
Parish & policy
St Mabyn is its own town in East Cornwall, with planning history that's specific to the PL30 catchment.
Coverage
We cover PL30 from our studio, with regular extension jobs also running in Wadebridge, Blisland, Bodmin. Most St Mabyn site visits get booked within the same week.
How quickly can you visit a St Mabyn site?
Usually within the same week. St Mabyn (PL30) is on our regular East Cornwall run, alongside Wadebridge, Blisland, Bodmin. First visits are free and you'll get an honest feasibility view inside seven days.
Request a free visitFAQs
St Mabyn 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 St Mabyn specifically, we'd start by checking the Conservation Area boundary 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.
- 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.
Other services in St Mabyn
Nearby places we cover
Designing a extension in St Mabyn is as much about reading the parish as reading the brief; we do both, and the planning outcomes follow.