West Cornwall · TR18
Design, planning and build for Heamoor 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. Every Heamoor project we take on begins with reading the local context — Heamoor is a residential village on the northern edge of Penzance, originally a separate hamlet, now effectively a suburb with its own primary school and parish identity, with a building stock that leans toward 1960s and 1970s estates and 1930s semis.
Heamoor sits in West Cornwall — covering TR18 from Penzance, Madron, Gulval outward.
- ✓ Plain-English feasibility before any drawings
- ✓ Free first site visit, no obligation
- ✓ Local to West Cornwall — not a national franchise
- ✓ Same team on paper as on site
Local proof — Most Heamoor extension clients we work with are second-time builders — they've seen the templated approach fail once already.
Get a free feasibility viewLocal context
Why Heamoor is its own job.
Cornwall Council's lens on Heamoor is consistent: within Madron parish; outside Conservation Area and AONB. Edge-of-Penzance development pressure has driven significant new estate housing in the last twenty years. For extension specifically, Heamoor sits outside the headline designations, which usually gives a slightly more flexible starting point — but parish-level character still matters. That's why we treat every Heamoor project as a TR18-area job first — not a generic Cornwall job with a postcode bolted on. The 1960s and 1970s estates that dominate Heamoor (and continue out toward Newlyn) 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 Heamoor.
01
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.
02
Cornish granite and slate-hung walls react differently to new openings than modern brickwork — lintel choice and structural sequencing matter.
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
Drainage on older Cornish properties is rarely on a clean modern map; CCTV survey before design is often money well spent.
Our process
How a Heamoor 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 Heamoor extension.
Building stock
Across Heamoor (TR18) we work on Victorian and Edwardian terraces, 1930s semis, 1960s and 1970s estates, modern new-build estates. Each stock type drives a different extension response — 1960s and 1970s estates in particular needs careful detailing here.
Parish & policy
Heamoor sits in the parish of Madron, which matters for how parish-level consultation lands on a extension application.
Coverage
We cover TR18 from our studio, with regular extension jobs also running in Penzance, Madron, Gulval. Most Heamoor site visits get booked within the same week.
How quickly can you visit a Heamoor site?
Usually within the same week. Heamoor (TR18) is on our regular West Cornwall run, alongside Penzance, Madron, Gulval. First visits are free and you'll get an honest feasibility view inside seven days.
Request a free visitFAQs
Heamoor Extensions — local questions answered.
- 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. In Heamoor 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.
- 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.
- 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.
Heamoor is part of Penzance
Heamoor sits inside the Penzance catchment — we cover both as one extension territory.
See Extensions in Penzance →Other services in Heamoor
Nearby places we cover
To sum up, our extension approach in Heamoor is built entirely around local Cornwall context, ensuring the best possible outcome for your property.