South Cornwall · TR11
House Extensions in Constantine
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 Constantine brief starts on the street, not the screen — Constantine is an AONB village inland from Helford on a steep granite hillside, with a substantial fifteenth-century church and a tight Conservation Area covering the village core, with a building stock that leans toward traditional granite cottages and Edwardian villas.
Constantine sits in South Cornwall — covering TR11 from Mawnan Smith, Gweek, Mabe Burnthouse outward.
- Conservation Area
- Cornwall AONB
- Rural / open-countryside policy area
- ✓ Local to South Cornwall — not a national franchise
- ✓ Same team on paper as on site
- ✓ Fixed-fee planning packages, no surprise invoices
- ✓ Measured-survey accuracy from day one
Local watch-list
Local snags worth knowing before drawing a Constantine extension.
Watch #1
Conservation Area material and fenestration controls in central Constantine
Watch #2
AONB landscape-impact scrutiny on visible elevations
Watch #3
Tighter Local Plan tests on isolated rural dwellings
Who this is for
Constantine runs the full mix — owner-occupier, holiday-let, commercial and the occasional smallholding — so we scope every extension enquiry from the use-class up.
Local context
Why Constantine is its own job.
Conservation Area covers the village including the church; AONB across the parish. Granite quarrying heritage and views to the Helford shape design considerations. For extension specifically, parts of Constantine sit within a designated Conservation Area, which means materials, fenestration and roof pitches all need to read sympathetically with the existing streetscape; 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. So every Constantine job runs as a TR11-specific piece of work — local policy, local fabric, local builders. Most of our extension work in Constantine lands on traditional granite cottages, with detailing that has to nod to the wider Mabe Burnthouse streetscape.
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 Constantine.
01
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
02
Wind and sea-spray exposure can drive material choices on west-facing extensions; we detail accordingly.
03
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.
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 Constantine 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
Constantine 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 Constantine specifically, we'd start by checking the Conservation Area boundary 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.
- 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.
Local proof — Recent extension enquiries from Constantine have clustered around traditional granite cottages — we know the route through Cornwall Council on these.
Get a free feasibility viewOther services in Constantine
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For Constantine homeowners weighing up a extension, the right starting point is honest feasibility — that's what we lead with, before any drawings.