East Cornwall · PL30
House Extensions in St Mabyn
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. In St Mabyn, that work is shaped by the place itself — 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 traditional granite cottages and Victorian villas.
- Conservation Area
- Rural / open-countryside policy area
Local context
Why St Mabyn is its own job.
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.
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
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.
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.
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.
FAQs
St Mabyn Extensions — common questions.
- 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.
Other services in St Mabyn
Nearby places we cover