Penwith · TR19
Botallack extension — feasibility first, drawings second
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. On a Botallack site, the brief always meets the place — Botallack is a former mining settlement in the TR19 area, with granite terraces, chapel buildings and industrial landscape character still visible, with a building stock that leans toward miners cottages and workers cottages.
Botallack sits in Penwith — covering TR19 from St Just in Penwith, Carnyorth, Kelynack outward.
- Cornwall AONB
- Cornish Mining World Heritage Site
- Rural / open-countryside policy area
- ✓ 30+ years of Cornwall Council approvals
- ✓ AONB experience built into the fee
- ✓ Cornwall Council regulars across every sub-area
- ✓ Free first site visit, no obligation
Who this is for
Botallack 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 watch-list
Common Botallack pitfalls we plan around.
Watch #1
AONB landscape-impact scrutiny on visible elevations
Watch #2
World Heritage Site assessment on changes visible in the mining landscape
Watch #3
Tighter Local Plan tests on isolated rural dwellings
Local proof — Recent extension enquiries from Botallack have clustered around miners cottages — we know the route through Cornwall Council on these.
Get a free feasibility viewFAQs
Botallack Extensions — local questions answered.
- 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. In Botallack specifically, we'd start by checking AONB landscape sensitivity before committing to a direction.
- 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.
- 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.
- 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.
Local context
Why Botallack is its own job.
Locally, mining heritage, old plot widths and traditional materials make proportion and detailing more important than generic extension templates. For extension specifically, 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; the wider area forms part of the Cornish Mining World Heritage Site, which adds a heritage assessment layer to most material changes; 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. Which is why we scope Botallack projects parish-up, not template-down — the TR19 context shapes the design from day one. Whether the project is on miners cottages in the centre or further out toward St Just in Penwith, the extension response is locally tuned.
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 Botallack.
01
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
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
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
Wind and sea-spray exposure can drive material choices on west-facing extensions; we detail accordingly.
Our process
How a Botallack 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 TR19.
Building stock
Across Botallack (TR19) we work on miners cottages, granite terraces, chapel conversions, workers cottages, post-war estates. Each stock type drives a different extension response — miners cottages in particular needs careful detailing here.
Parish & policy
Botallack sits in the parish of Botallack, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover TR19 from our studio, with regular extension jobs also running in St Just in Penwith, Carnyorth, Kelynack. Most Botallack site visits get booked within the same week.
What does a first Botallack consultation cost?
Nothing. We come to the property, walk the site, talk through what works on a TR19 plot and follow up with a written feasibility note inside a week — no obligation either way.
Request a free visitBotallack is part of St Just in Penwith
Botallack sits inside the St Just in Penwith catchment — we cover both as one extension territory.
See Extensions in St Just in Penwith →Other services in Botallack
Nearby places we cover
From initial feasibility to final handover, we manage extension projects across Botallack with careful attention to what makes Penwith unique.