East Cornwall · PL12
Extensions for St Mellion (PL12)
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. St Mellion sits in East Cornwall, and that geography ends up in the drawings — St Mellion is an estate-influenced village in the PL12 area, with designed landscape, older cottages and rural edges close together, with a building stock that leans toward detached homes and small infill plots.
St Mellion sits in East Cornwall — covering PL12 from Saltash, Hatt, Landrake outward.
- Rural / open-countryside policy area
- ✓ One studio — design, planning and build under one roof
- ✓ Local to East Cornwall — not a national franchise
- ✓ Measured-survey accuracy from day one
- ✓ Cornwall Council regulars across every sub-area
Our process
How a St Mellion 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 proof — Most St Mellion extension clients we work with are second-time builders — they've seen the templated approach fail once already.
Get a free feasibility viewWhat we focus on
Extensions considerations specific to St Mellion.
01
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
02
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.
03
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.
04
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
Local context
Why St Mellion is its own job.
In St Mellion the planning picture is specific: landscape setting, curtilage history and estate character need a precise design rationale rather than a standard suburban approach. 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 local reading is what makes a St Mellion (PL12) project different from a generic Cornwall scheme — and is the whole reason we work this way. On detached homes in particular — the kind you'll also find toward Tideford — the extension brief always has to read the existing fabric first.
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.
Local watch-list
What usually catches extension projects out in St Mellion.
Watch #1
Tighter Local Plan tests on isolated rural dwellings
St Mellion is part of Saltash
St Mellion sits inside the Saltash catchment — we cover both as one extension territory.
See Extensions in Saltash →Local fabric
St Mellion extensions — the local-studio difference.
Building stock
Across St Mellion (PL12) we work on estate cottages, farm buildings, detached homes, converted outbuildings, small infill plots. Each stock type drives a different extension response — detached homes in particular needs careful detailing here.
Parish & policy
St Mellion sits in the parish of St Mellion, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover PL12 from our studio, with regular extension jobs also running in Saltash, Hatt, Landrake. Most St Mellion site visits get booked within the same week.
Can you handle both planning and build in St Mellion?
Yes — design, planning, building regs and full construction run under one roof. For clients with an existing St Mellion builder we can stop at a tender-ready Full Plans pack instead.
Request a free visitWho this is for
St Mellion runs the full mix — owner-occupier, holiday-let, commercial and the occasional smallholding — so we scope every extension enquiry from the use-class up.
FAQs
St Mellion Extensions — local questions answered.
- 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. In St Mellion specifically, we'd start by checking the latest parish-level planning history before committing to a direction.
- 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.
- 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.
Other services in St Mellion
Nearby places we cover
Every St Mellion extension we work on is treated as a PL12 job in its own right — local fabric, local policy, local builders.