East Cornwall · PL12
Design, planning and build for St Germans 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. A PL12 site visit comes before a St Germans sketch, every time — St Germans is a creekside settlement in the PL12 area, with waterside homes, wooded valleys and narrow-lane access shaping the brief, with a building stock that leans toward waterside homes and converted barns.
St Germans sits in East Cornwall — covering PL12 from Saltash, Hatt, Landrake outward.
- Conservation Area
- ✓ Conservation Area experience built into the fee
- ✓ 30+ years of Cornwall Council approvals
- ✓ Measured-survey accuracy from day one
- ✓ One studio — design, planning and build under one roof
Local proof — Most St Germans homeowners come to us after a extension quote elsewhere felt vague on planning — we lead with feasibility instead.
Get a free feasibility viewLocal context
Why St Germans is its own job.
Cornwall Council's lens on St Germans is consistent: creekside ecology, flood risk, trees and views across the water often matter as much as the building form itself. For extension specifically, parts of St Germans sit within a designated Conservation Area, which means materials, fenestration and roof pitches all need to read sympathetically with the existing streetscape. That's why we treat every St Germans project as a PL12-area job first — not a generic Cornwall job with a postcode bolted on. The waterside homes that dominate St Germans (and continue out toward Landrake) 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 Germans.
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
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
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 St Germans 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 PL12.
Building stock
Across St Germans (PL12) we work on creekside cottages, detached houses, boat sheds, converted barns, waterside homes. Each stock type drives a different extension response — waterside homes in particular needs careful detailing here.
Parish & policy
St Germans sits in the parish of St Germans, 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 Germans site visits get booked within the same week.
How quickly can you visit a St Germans site?
Usually within the same week. St Germans (PL12) is on our regular East Cornwall run, alongside Saltash, Hatt, Landrake. First visits are free and you'll get an honest feasibility view inside seven days.
Request a free visitFAQs
St Germans 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 Germans 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.
- 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.
- 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.
St Germans is part of Saltash
St Germans sits inside the Saltash catchment — we cover both as one extension territory.
See Extensions in Saltash →Other services in St Germans
Nearby places we cover
Most St Germans extension enquiries start with one honest conversation about what's actually allowed — and that conversation costs nothing.