West Cornwall · TR20
Crowlas extensions — a West Cornwall studio
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. Anchor any Crowlas extension in the local fabric and the rest follows — Crowlas is a commuter village in the TR20 area, with everyday family housing, edge-of-village plots and quick routes to its parent town, with a building stock that leans toward post-war semis and bungalows.
Crowlas sits in West Cornwall — covering TR20 from Penzance, Chyandour, Sancreed outward.
- Cornish Mining World Heritage Site
- ✓ World Heritage Site experience built into the fee
- ✓ Cornwall Council regulars across every sub-area
- ✓ 30+ years of Cornwall Council approvals
- ✓ Fixed-fee planning packages, no surprise invoices
Who this is for
Crowlas 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
Crowlas-specific issues we screen on the first visit.
Watch #1
World Heritage Site assessment on changes visible in the mining landscape
Local proof — Recent extension enquiries from Crowlas have clustered around post-war semis — we know the route through Cornwall Council on these.
Get a free feasibility viewFAQs
Crowlas 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 Crowlas specifically, we'd start by checking the latest parish-level planning history before committing to a direction.
- 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.
- 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.
Local context
Why Crowlas is its own job.
The planning backdrop in West Cornwall is real, not abstract: applications here usually turn on neighbour amenity, parking, overlooking and whether new work fits the rhythm of existing streets. For extension specifically, the wider area forms part of the Cornish Mining World Heritage Site, which adds a heritage assessment layer to most material changes. Treat the TR20 parish brief as the design brief and the Crowlas application has somewhere to land. Whether the project is on post-war semis in the centre or further out toward Penzance, 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 Crowlas.
01
Wind and sea-spray exposure can drive material choices on west-facing extensions; we detail accordingly.
02
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
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 Crowlas 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
Why a West Cornwall studio is the right fit for Crowlas extension.
Building stock
Across Crowlas (TR20) we work on post-war semis, bungalows, modern estates, older cottages, garden infill plots. Each stock type drives a different extension response — post-war semis in particular needs careful detailing here.
Parish & policy
Crowlas sits in the parish of Crowlas, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover TR20 from our studio, with regular extension jobs also running in Penzance, Chyandour, Sancreed. Most Crowlas site visits get booked within the same week.
What does a first Crowlas consultation cost?
Nothing. We come to the property, walk the site, talk through what works on a TR20 plot and follow up with a written feasibility note inside a week — no obligation either way.
Request a free visitCrowlas is part of Penzance
Crowlas sits inside the Penzance catchment — we cover both as one extension territory.
See Extensions in Penzance →Other services in Crowlas
Nearby places we cover
A extension in Crowlas stands or falls on how well it reads the street — we treat that as the design brief, not an afterthought.